bluuebunny/crossref_metadata_2025_split huggingface dataset:
Emulsion Polymerization
Authors: van Herk A. , Heuts H. 
Published: April 2009

Abstract
The production of polymers is shifting from solvent‐based systems toward water‐based systems. A versatile technique to produce polymer nanoparticles in an aqueous system is emulsion polymerization. Different aspects described in this article are the general mechanism of emulsion polymerization, ingredients in the recipes, emulsion copolymerization and composition drift, process strategies, development of particle morphologies, reactor setups and industrial‐scale operation aspects of mixing and heat transfer, and finally the main applications of latices.
Ion Exchange Technology
Authors: Sarkar Sudipta , Greenleaf John E. , SenGupta Arup K. 
Published: April 2009

AbstractSince its discovery more than a century ago, the phenomenon of ion exchange has undergone significant evolution in terms of both theory and practice, especially after the synthesis of organic (polymeric) ion exchangers. No specialty thrives in isolation. The field of ion exchange grew over decades by permeating into myriad areas from deionization to drug delivery. There have been continuous development in the synthesis of new ion exchange materials and processes that now cater to various applications in industries as diverse as power and water utilities, biotechnology, chemical purification, food and beverages, agriculture, pharmaceuticals, microelectronics, and also water treatment. Polymeric ion exchangers, viewed as a strongly ionized electrolyte with low dielectric constants, can be made suitable for various uses including trace contaminant removal in environmental separation, hydrometallurgy, catalysis, product purification, and sustainable industrial processes. Many of these specific interactions can be characterized and enhanced by making modifications to the polymer matrix, covalently attached fixed functional groups, degree of cross‐linking, porosity, and morphology. Affinity for specific ions or selectivity of the ion exchangers plays a critical role and allows one to design ion exchange processes in which complete removal of the target ion from the background of other ions is required. Selectivity of the ion exchangers also influences separation of noble metals and chemical purification operations. An understanding of the basic principles of ion exchange equilibrium and kinetics is important for the development of new materials and processes. In order for an ion exchange process to be economically viable, the ion exchangers need to be regenerable so that they may be used for tens of cycles. Such a constraint demands a tradeoff between the high selectivity of the resin and its regenerability with cost‐effective regenerants. Regulations related to the disposal of spent regenerant have also driven new advancements in the field of ion exchange.
Polymer Filtration Membranes
Authors: Asatekin Ayse , Mayes Anne M. 
Published: April 2009

AbstractPolymer filtration membranes have been a focus of research since the late eighteenth century and became a thriving industry in the twentieth century. Today, membranes are used in commercial applications spanning from drinking water purification to gas separations, with a market that is expected to grow to more than $10 billion by 2010. This article describes the materials and morphologies commonly found in today's commercial membranes, along with their methods of manufacture. Membranes classified according to retentate size as microfiltration, ultrafiltration, nanofiltration, or reverse osmosis are introduced, along with ion exchange and gas separation membranes. The primary mechanisms by which these different membranes achieve separation during filtration are described, as well as example applications. Permeability, molecular weight cutoff, and rejection/retention are introduced as metrics for membrane performance comparisons. Membrane fouling is discussed as a chief obstacle to the more widespread use of membranes in wastewater treatment and other applications involving high concentrations of organics in the feed stream. Mechanisms of membrane fouling are described along with approaches commonly employed to limit fouling, including membrane surface modification, process optimization, and pretreatment of the feed. The future outlook of the polymer filtration membrane industry is touched upon in the context of increasing demand for fresh water and continuing improvements in membrane performance anticipated by research advances.
Modified synthetic aperture algorithm for sonar systems
Authors: Sawa T. , Aoki T. , Yoshida H. , Hyakudome T. , Ishibashi S. , Matsubara S. , Wright S. 
Published: April 2009

AbstractIt is hard to negate the effects of ocean waves on synthetic aperture sonar that has to be operated in the ocean and many efforts to deal with ocean waves have been made. One of these efforts is motion compensation by calculating phase errors with a computer. But the synthetic aperture algorithm with motion compensation is heavy, and remains difficult to be executed on a real‐time basis. Thus, a modified synthetic aperture algorithm is proposed in this paper. This algorithm, which is named a 1.5‐dimensional algorithm, is in between a one‐dimensional and two‐dimensional algorithm. It synthesizes a virtual aperture about 10 times faster than other algorithms in a computer simulation. Copyright © 2009 John Wiley & Sons, Ltd.
Solution Processing of Chalcogenide Semiconductors via Dimensional Reduction
Authors: Mitzi David B. 
Published: April 2009

AbstractThe quest to develop thin‐film solution processing approaches that offer low‐cost and preferably low‐temperature deposition, while simultaneously providing quality semiconductor characteristics, has become an important thrust within the materials community. While inorganic compounds offer the potential for outstanding electronic properties relative to organic systems, the very nature of these materials rendering them good electronic materials—namely strong covalent bonding—also leads to poor solubility. This review presents a “dimensional reduction” approach to improving the solubility of metal chalcogenide semiconductors, which generally involves breaking the extended framework up into discrete metal chalcogenide anions separated by small and volatile cationic species. The resulting soluble precursor may be solution‐processed into thin‐film form and thermally decomposed to yield the desired semiconductor. Several applications of this principle to the solution deposition of high‐performance active layers for transistors (channel mobility >10 cm2 V−1 s−1), solar cells (power conversion efficiency of as high as 12%), and fundamental materials study will be presented using hydrazine as the deposition solvent.
Self‐Assembled Quantum Dot Molecules
Authors: Wang Lijuan , Rastelli Armando , Kiravittaya Suwit , Benyoucef Mohamed , Schmidt Oliver G. 
Published: April 2009

AbstractSemiconductor quantum dot molecules (QDMs) are systems composed of two or more closely spaced and interacting QDs. QDMs are receiving much attention both as playground for studying coupling and energy transfer processes between “artificial atoms” and as new systems, which substantially extend the range of possible applications of QDs. QDMs can be conveniently fabricated by self‐assembly either through chemical synthesis or epitaxial growth. Although QDMs relying on the random occurrence of nearby QDs can be used for fundamental studies, special fabrication protocols must be used to create QDMs with well‐defined properties. In this article, we focus on self‐assembled QDMs obtained by epitaxial growth and embedded in a semiconductor matrix, which are appealing for the possible realization of quantum gates based on two‐level systems defined in QDs. We provide a comprehensive overview of the development and current stage of the research on QDMs composed of vertically (in the growth direction) or laterally (in the growth plane) aligned QDs. The review highlights some recent milestone works and points out the challenges and future directions in the field.
Socioeconomic variation in the growth status of urban school children 6–13 years in Oaxaca, Mexico, in 1972 and 2000
Authors: Malina Robert M. , Peña Reyes Maria Eugenia , Little Bertis B. 
Published: April 2009

AbstractSocioeconomic variation in the growth status of urban school children 6–13 years of age in 1972 and 2000 was compared. The children were resident in the city of Oaxaca and were students in the same primary school in each year. Socioeconomic status (SES) was based on parental occupation. Height, sitting height, estimated leg length, weight, and the body mass index in 218 boys and 191 girls in 1972 and 173 boys and 166 girls in 2000 were compared. Sex‐specific MANCOVA was used to evaluate SES differences within each year, while sex‐ and SES‐specific MANCOVA was used to evaluate differences between years. The prevalence of stunting, overweight and obesity was estimated. There were no SES differences among boys and girls in 1972 and boys in 2000; low‐middle and middle SES girls were significantly taller and heavier with longer legs than low SES girls in 2000. Within each SES group, children in 2000 were significantly larger in body size and segment lengths except for sitting height in low SES children of both sexes. Estimated secular gains increased from low to low‐middle to middle SES in both sexes. Inequitable gains by SES contributed to an increase in the magnitude of differences between SES groups, especially between low SES children on one hand and low‐middle and middle SES children on the other hand. The prevalence of stunting declined while the prevalence of overweight and to a lesser extent in obesity increased from 1972 to 2000, more so in low‐middle and middle SES than in low SES children. Am. J. Hum. Biol. 2009. © 2009 Wiley‐Liss, Inc.
The Garífuna (Black Carib) people of the Atlantic coasts of Honduras: Population dynamics, structure, and phylogenetic relations inferred from genetic data, migration matrices, and isonymy
Authors: Herrera‐Paz Edwin‐Francisco , Matamoros Mireya , Carracedo Ángel 
Published: April 2009

AbstractThe aim of this study is to assess population dynamics, structure, and phylogenetic relations of the populations that inhabit the Caribbean coasts of Honduras: the Garífuna (or Black Carib) people, an admixture of Black Africans and Red Carib Native Amerindians. Thirteen autosomal tetranucleotide microsatellite markers of the DNA (namely short tandem repeats) were genotyped in samples from the Garifuna communities of Bajamar, in the Department of Cortés; Corozal, in the Department of Atlántida; and Iriona, in the Department of Gracias a Dios. Each subject in the study filled a questionnaire with the following information: complete name and surname of participant, and places of birth of the participant, his/her parents, and grandparents. We performed analyses that included determination of migration rates and residence patterns from information of places of birth, fixation indices from genetic data, and analysis of surnames of the sampled subjects (isonymy). Migration matrices showed a migration wave from east to west in the parents and grandparents of the subjects. A raise in migration rates and a shift in predominating residence pattern from neolocality to matrilocality from grandparents to parents were observed. Analysis of isonymy conjunctly with values for FIS in each community showed high endogamy in Bajamar, and recent, high immigration in Iriona. A dendrogram constructed with allele frequencies of the Garifuna and other populations from the Americas, Africa, and Europe revealed the close relationships of this ethnic group with Afro‐Caribbean and African Populations. Am. J. Hum. Biol. 2010. © 2009 Wiley‐Liss, Inc.
Fetal signaling through placental structure and endocrine function: Illustrations and implications from a nonhuman primate model
Authors: Rutherford Julienne N. 
Published: April 2009

AbstractThe placenta is a transmitter of fetal need and fetal quality, interfacing directly with maternal physiology and ecology. Plasticity of placental structure and function across the developmental timeframe of gestation may serve as an important tool by which a fetus calibrates its growth to shifting maternal ecology and resource availability, and thereby signals its quality and adaptability to a changing environment. Signals of this quality may be conveyed by the size of the placental interface, an important marker of fetal access to maternal resources, or by production of placental insulin‐like growth factor‐II, a driver of fetoplacental growth. Litter size variation in the common marmoset monkey offers the opportunity to explore intrauterine resource allocation and placental plasticity in an important nonhuman primate model. Triplet marmosets are born at lower birth weights and have poorer postnatal outcomes and survivorship than do twins; triplet placentas differ in placental efficiency, microscopic morphology, and endocrine function. Through placental plasticity, triplet fetuses are able to adjust functional access to maternal resources in a way that allows pregnancy to proceed. However, the costs of such mechanisms may relate to reduced fetal growth and altered postnatal outcomes, with the potential to lead to adverse adult health consequences, suggesting an important link between the placenta itself and the developmental origins of health and disease. Am. J. Hum. Biol. 2009. © 2009 Wiley‐Liss, Inc.
Age at first reproduction and economic change in the context of differing kinship ecologies
Authors: Leonetti Donna L. , Nath Dilip C. 
Published: April 2009

AbstractKinship systems which tend to be based on ecologies of subsistence also assign differential power, privilege, and control to human connections that present pathways for manipulation of resource access and transfer. They can be used in this way to channel resource concentrations in women and hence their reproductive value. Thus, strategic female life course trade‐offs and their timing are likely to be responsive to changing preferences for qualities in women as economic conditions change. Female life histories are studied in two ethnic groups with differing kinship systems in NE India where the competitive market economy is now being felt by most households. Patrilineal Bengali (599 women) practice patrilocal residence with village exogamy and matrilineal Khasi (656 women) follow matrilocal residence with village endogamy, both also normatively preferring three‐generation extended households. These households have helpful senior women and significantly greater income. Age at first reproduction (AFR), achieved adult growth (height) and educational level (greater than 6 years or less) are examined in reproductive women, ages 16–50. In both groups, women residing normatively are older at AFR and taller than women residing nonnormatively. More education is also associated with senior women. Thus, normative residence may place a woman in the best reproductive location, and those with higher reproductive and productive potential are often chosen as households face competitive market conditions. In both groups residing in favorable reproductive locations is associated with a faster pace of fertility among women, as well as lower offspring mortality among Khasi, to compensate for a later start. Am. J. Hum. Biol., 2009. © 2009 Wiley‐Liss, Inc.
Ritualized combat as an indicator of intrasexual selection effects on male life history evolution
Authors: Graves Brent M. 
Published: April 2009

AbstractTrade‐offs between survival, growth, current reproduction, and future reproduction influence life history evolution, leading to adaptive timing of investment in various strategies. If engagement in costly intrasexual contests to gain better access to mates is an important form of male reproductive investment, then the expression of characters that promote success in this process should be influenced by their fitness effects across the lifespan. To test this prediction, the ages at which human (Homo sapiens) males exhibit the greatest investment in morphological, behavioral, and physiological characters associated with intrasexual competition was estimated by examining the ages at which males succeed in a form of ritualized combat. The average age of international boxing champions was in the latter half of the twenties, and titles were held for about 2 years on average. Thus, peak investment in traits that enhance intrasexual competition abilities appears to coincide with ages at which males have highest reproductive success. Additionally, larger males reached peak probability of success in this ritualized combat at ages about 2.6 years greater than smaller males. Because body size is highly heritable and there is strong positive assortative mating relative to this character among humans, this may indicate a polymorphic set of reproductive strategies produced through maintenance of coadapted gene complexes. Am. J. Hum. Biol., 2010. © 2009 Wiley‐Liss, Inc.
Enzymkatalyse “in neuem Licht”
Authors: Gärtner Wolfgang 
Published: April 2009

AbstractBei Licht betrachtet: Die NADPH:Protochlorophyllid(Pchlid)‐Oxidoreduktase (POR; siehe Struktur; grün Pchlid, gelb NADPH) ist ein gutes Modell für die Untersuchung katalytischer Prozesse in Enzymen, denn ihre Lichtaktivierung ermöglicht einen sofortigen Start der katalysierten Reaktion. Durch Bestrahlung mit schwachen, kurzen Laserpulsen kann man Konformationsänderungen während der Reaktion detektieren und so den Katalyseprozess in seine Einzelschritte zerlegen.magnified image
Enzyme Catalysis “Reilluminated”
Authors: Gärtner Wolfgang 
Published: April 2009

AbstractIn a new light: The NADPH:protochlorophyllide (Pchlide) oxidoreductase (POR; see structure, green Pchlide, yellow NADPH) is a good model to investigate catalytical processes in enzymes, as its light activation allows an immediate start of the catalyzed reaction. By irradiation with weak, short laser pulses it is possible to detect conformation changes during the reaction and thus to uncover the elementary steps of the catalytic process.magnified image
Correlation of the Mitochondrial Activity of Two‐Cell Embryos Produced In Vitro and the Two‐Cell Block In Kunming and B6C3F1 Mice
Authors: Wang Shie , Lin Cuiying , Shi Hexiu , Xie Meirong , Zhang Weiyu , Lv Junjie 
Published: April 2009

AbstractThe correlation between the early embryonic block to development and mitochondrial activity was investigated comparing two‐cell embryos produced in vitro from Kunming (KM) and B6C3F1 mice. One‐cell embryos were obtained from two species of hybrids (female KM mice mated with KM males and female B6C3F1 mice mated with KM males) and cultured for 84 hr in M16 media. The mitochondrial membrane potential, ATP content, and reactive oxygen species levels were measured in the resulting KM and B6C3F1 two‐cell embryos. Mitochondrial membrane potential and ATP content were also determined in KM and B6C3F1 metaphase II eggs. The results showed that the two‐cell block was observed in cultured KM embryos but not in B6C3F1 embryos. Mitochondrial membrane potential and ATP content of KM two‐cell embryos were significantly lower than in B6C3F1 two‐cell embryos (P < 0.01). Interestingly, the reactive oxygen species levels of KM two‐cell embryos were significantly lower than their B6C3F1 counterparts (P < 0.01). There was no difference in mitochondrial membrane potential and ATP content between KM and B6C3F1 metaphase II eggs. It is concluded that KM mice have an early two‐cell embryo block and that a possible “blocking” mechanism is the lower mitochondrial membrane potential and ATP content in these embryos. The results suggest a new approach for overcoming early embryonic development block, that of manipulating mitochondrial activity. Anat Rec, 292:661–669, 2009. © 2009 Wiley‐Liss, Inc.
Geometric Morphometric Investigation of Molar Shape Diversity in Modern Lemurs and Lorises
Authors: White Jess 
Published: April 2009

AbstractIn the study of mammalian adaptation to the environment, teeth are of primary importance due to their role as one of the direct interaction points between an individual and its ecological surroundings. Here, molar shape and function are investigated through traditional multivariate statistics and Thin‐Plate Splines deformations to compare the relative location of lower first molar occlusal structures (protoconid, metaconid, hypoconid, entoconid, cristid obliqua, and protolophid) in modern lemurs, lorises, tarsiers, and a non‐primate outgroup taxon (Tupaia). Results suggest that shape is based both on tooth size and dietary patterns. Small teeth tend to be short (anteroposteriorally) with wide talonids, whereas larger teeth are generally characterized as being long and narrow. In considering non‐size related shape trends, frugivorous and graminivorous taxa generally exhibit a relatively buccal intersection of the cristid obliqua with the base of the protolophid, and a relatively “perpendicular” position of the protolophid in relation to the anteroposterior axis of the tooth (defined as the axis connecting the protolophid and hypoconid). Morphological trends of folivores include a central (midline) position of the cristid obliqua‐protolophid base intersection and an oblique angle of the protolophid. Insectivorous taxa (primate and non‐primate) generally exhibit a central placement of the cristid obliqua‐protolophid base intersection (as in folivores), along with a relatively perpendicular angle of the protolophid (as in frugivores). Omnivorous taxa exhibit shape patterns that are intermediate between these three former groups. This study provides a comparative baseline for the interpretation of morphological trends in fossil primate groups, particularly the Adapiformes. Anat Rec, 292:701–719, 2009. © 2009 Wiley‐Liss, Inc.
Mean–variance efficiency with extended CIR interest rates
Authors: Ferland René , Watier François 
Published: April 2009

AbstractWe study a mean–variance investment problem in a continuous‐time framework where the interest rates follow Cox–Ingersoll–Ross dynamics. We construct a mean–variance efficient portfolio through the solutions of backward stochastic differential equations. We also give sufficient conditions under which an explicit analytic expression is available for the mean–variance optimal wealth of the investor. Copyright © 2009 John Wiley & Sons, Ltd.