bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic Polymers
Authors: Nishide Hiroyuki , Suga Takeo 
Published: July 2011

Abstract
Discovery of doped polyacetylenes and the following extensive investigations of π‐conjugated conducting polymers also evoked the attempt creating magnetic organic polymers. In the last two decades, theoretical and experimental studies on π‐conjugated organic molecules bearing plural unpaired electrons have elucidated a clear correlation between the molecular connectivity or substitution positions of the radical groups on the conjugated skeleton and spin multiplicity or spin quantum number (S) at a ground state. A stabilized high‐spin state (spin alignment, S > 2/2) among the plural unpaired electrons was achieved based on an intramolecular and strong through‐bond spin‐exchange interaction through pi‐conjugation. Here we start with molecular structure‐S correlation of diradical model molecules as an example, and then extend the criteria for designing high‐spin organic polymers. The highest spin alignment (S) value of the polymers has been improved year by year through two main molecular design approaches: (i) π‐conjugated polymers bearing pendant radical groups, and (ii) cross‐conjugated, radical‐integrated polymers. Advantages and limitations of these two approaches are described, and the two‐dimensionally extended organic polyradical molecules (hyperbranched and/or cross‐conjugated network) are highlighted in this chapter. The molecular‐based, tunable magneto‐responsible polymer dots can lead to the potential application for the magnetic information storage, and the opto‐magnetic and electro‐magnetic properties of the polyradicals are promising field. The high‐spin organic polyradical molecules with chemical stability, flexibility, plasticity, and moldability will open a new field of magnetic organic materials.
Dyes, Macromolecular
Authors: Guthrie J. T. , Magami S. M. , Puthiyottil R. 
Published: July 2011

AbstractThe review concerns the science, technology and applications of macromolecular dyes and colorants. The approach considers some of the important synthesis routes to such species, and their applications, dealt with in a chronological order. The concepts that underpin the creation of macromolecular dyes are considered as are the strategies for the creation of a wide variety of variants.
Theoretical Aspects of Organoselenium Chemistry
Authors: Sunoj Raghavan B. 
Published: July 2011

AbstractThe chapter offers an overview of the applications of theoretical methods in the area of organoselenium chemistry. In recent years, the availability of reliable basis sets and computational methods, especially the emergence of density functional methods, have enabled studies on increasingly complex chemical problems. A plethora of such problems in organoselenium chemistry and interesting insights on structure, properties, and reactions derived by using computational methods constitute the contents of this chapter. The types of situations described range from exotic briefly lived intermediates to structural and electronic features of stable and crystalline molecules. Properties such as nuclear magnetic resonance chemical shift and the comparison between computed and experimental quantities have been provided extensively. A number of reactions of selenium compounds with emphasis on biologically significant reactions have been highlighted. In particular, computational studies on glutathione peroxidate activity of selenium compounds have been elaborated. The electronic origins of inter‐ and intra‐molecular nonbonding interactions in organoselenium compounds and an illustration of how theoretical methods have been vital in quantifying such weak interactions have been provided.
Depicting the Missing: Prospective and Retrospective Person Memory for Age Progressed Images
Authors: Lampinen James Michael , Miller Justin T. , Dehon Hedwige 
Published: July 2011

SummaryOne approach that has been used to help recover missing children is forensic age progression. In forensic age progression, outdated photographs of missing children are aged to provide an estimate of the current appearance of the child. We examined the effectiveness of age progressed images in the context of both prospective person memory and retrospective person memory. Memory for outdated and age progressed images did not significantly differ. Moreover, there was some indication that age progressed images were associated with a more conservative response bias. The results failed to demonstrate an advantage for age progressed pictures. Copyright © 2011 John Wiley & Sons, Ltd.
Confined Ferroelectric Properties in Poly(Vinylidene Fluoride‐co‐Chlorotrifluoroethylene)‐graft‐Polystyrene Graft Copolymers for Electric Energy Storage Applications
Authors: Guan Fangxiao , Yang Lianyun , Wang Jing , Guan Bing , Han Kuo , Wang Qing , Zhu Lei 
Published: July 2011

AbstractDielectric polymer film capacitors having high energy density, low loss and fast discharge speed are highly desirable for compact and reliable electrical power systems. In this work, we study the confined ferroelectric properties in a series of poly(vinylidene fluoride‐co‐chlorotrifluoroethylene)‐graft‐polystyrene [P(VDF‐CTFE)‐g‐PS] graft copolymers, and their potential application as high energy density and low loss capacitor films. Thin films (ca. 20 μm) are prepared by different processing methods, namely, hot‐pressing or solution‐casting followed by mechanical stretching at elevated temperatures. After crystallization‐induced microphase separation, PS side chains are segregated to the periphery of PVDF crystals, forming a confining interfacial layer. Due to the low polarizability of this confining PS‐rich layer at the amorphous–crystalline interface, the compensation polarization is substantially decreased resulting in a novel confined ferroelectric behavior in these graft copolymers. Both dielectric and ferroelectric losses are significantly reduced at the expense of a moderate decrease in discharged energy density. Our study indicates that the best performance is achieved for a P(VDF‐CTFE)‐g‐PS graft copolymer with 34 wt‐% PS; a relatively high discharged energy density of approximately 10 J cm−3 at 600 MV m−1, a low dielectric loss (tanδ = 0.006 at 1 kHz), and a low hysteresis loop loss (17.6%) at 550 MV m−1.
Solution‐Processed Organic Light‐Emitting Transistors Incorporating Conjugated Polyelectrolytes
Authors: Seo Jung Hwa , Namdas Ebinazar B. , Gutacker Andrea , Heeger Alan J. , Bazan Guillermo C. 
Published: July 2011

AbstractImproved performance of p‐type organic light‐emitting transistors (OLETs) is demonstrated by introducing a conjugated polyelectrolyte (CPE) layer and symmetric high work function (WF) source and drain metal electrodes. The OLET comprises a tri‐layer film consisting of a hole transporting layer, an emissive layer, and a CPE layer as an electron injection layer. The thickness of the CPE layer is critical for achieving good performance and provides an important structural handle for consideration in future optimization studies. We also demonstrate for the first time, good performance solution‐processed blue‐emitting OLETs. These results further demonstrate the simplification of device fabrication and improved performance afforded by integrating CPE interlayers into organic optoelectronic devices.
P3HT:PCBM, Best Seller in Polymer Photovoltaic Research
Authors: Dang Minh Trung , Hirsch Lionel , Wantz Guillaume 
Published: July 2011

AbstractIn the field of polymer‐based photovoltaic cells, poly(3‐hexylthiophene) (P3HT) and 1‐(3‐methoxycarbonyl)propyl‐1‐phenyl[6,6]C61 (PCBM) are, to date, the most‐studied active materials around the world for the bulk‐heterojunction structure. Various power‐conversion efficiencies are reported up to approximately 5%. This Research News article is focused on a survey of the tremendous literature published between 2002 and 2010 that exhibits solar cells based on blends of P3HT and PCBM.
Manganese Oxide/Carbon Aerogel Composite: an Outstanding Supercapacitor Electrode Material
Authors: Lin Yu‐Hsun , Wei Te‐Yu , Chien Hsing‐Chi , Lu Shih‐Yuan 
Published: July 2011

AbstractManganese oxide/carbon aerogel composite electrodes are prepared by a self‐limiting anodic‐electrochemical deposition of manganese oxide into a binder‐enriched carbon aerogel layer, drop‐cast on a graphite substrate, using 0.1 M Mn(CH3COO)2·4H2O as the electrolyte. Manganese oxide grows in the form of thin nanofibers along the backbone of the carbon aerogel, leaving adequate working space for the electrolyte and enabling a fuller extent of the utilization of the manganese oxide to make the composite an outstanding supercapacitor electrode material. The manganese oxide is determined to be Mn3O4 with the Raman spectroscopy and high‐resolution transmission electron microscopy. The rectangularity of the cyclic‐voltammogram loops of the composite electrode is excellent and remains that way for scan rates up to a very‐high value of 500 mV s−1, indicating extremely good redox reversibility and cycle efficiency. At a scan rate of 25 mV s−1, the specific capacitance, as measured in 0.5 M Na2SO4 for a potential window of 0.1–0.9 V vs. Ag/AgCl, reaches a maximum value of 503 F g−1 and experiences only a negligible decay of less than 1% at the 6000th cycle, implying an extraordinary cycling stability. The cycling efficiency is as high as 98% at a current density of 8 A g−1 cm−2, showing an almost‐ideal capacitive behavior. The power density reaches 48.5 kW kg−1 and the energy density 21.6 W h kg−1 at a scan rate of 500 mV s−1, well above the specifications of current state‐of‐the‐art supercapacitors.
Numerical simulation of the wire‐pinning process in PET film casting: Steady‐state results
Authors: Christodoulou Kostas , Hatzikiriakos Savvas G. , Mitsoulis Evan 
Published: July 2011

AbstractPoly(ethylene terephthalate) (PET) film casting involves melt flow through a slot die, across a small span, and onto a fast moving quench drum. In the “wire‐pinning” casting process, a thin electrified wire close to the line of contact with the drum creates a strong pinning force that delays air entrainment to higher line speeds. Nonuniform wetting of the die lips by the extruded melt is thought to be responsible for the formation of streaks, a defect in the machine direction. A finite element model of the film casting process with wire pinning was developed to assist in understanding what causes significant wetting of the lips and whether this can be avoided by electrostatic pinning. The solution of the governing equations provide the location of the static and dynamic contact lines, thus finding the wetting and pinning points in the process. The simulations investigate the sensitivity of the static wetting line locations on the die lands to the imposed values of static contact angle and die‐lip gap. It was found that while the contact angle has a small effect on the extent of die‐lip wetting within the parameter ranges examined, there is a considerable chance that the feed slot surfaces can be dewetted. This seems to be the greatest danger for causing streaks rather than excessive wetting of the die lands. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Detailed modeling of the evaporation and thermal decomposition of urea‐water solution in SCR systems
Authors: Ebrahimian Vahid , Nicolle Andre , Habchi Chawki 
Published: July 2011

AbstractThis work is aimed to develop a multicomponent evaporation model for droplets of urea‐water solution (UWS) and a thermal decomposition model of urea for automotive exhausts by using the selective catalytic reduction systems. In the multicomponent evaporation model, the influence of urea on the UWS evaporation is taken into account using a nonrandom two‐liquid activity model. The thermal decomposition model is based on a semidetailed kinetic scheme accounting not only for the production of ammonia (NH3) and isocyanic acid but also for the formation of heavier solid by‐products (biuret, cyanuric acid, and ammelide). This kinetics model has been validated against gaseous data as well as solid‐phase concentration profiles obtained by Lundstroem et al. (2009) and Schaber et al. (2004). Both models have been implemented in IFP‐C3D industrial software to simulate UWS droplet evaporation and decomposition as well as the formation of solid by‐products. It has been shown that the presence of the urea solute has a small influence on the water evaporation rate, but its effect on the UWS temperature is significant. In addition, the contributions of hydrolysis and thermolysis to urea decomposition have been assessed. Finally, the impacts of the heating rate as well as gas‐phase chemistry on urea decomposition pathways have been studied in detail. It has been shown that reducing the heating rate of the UWS causes the extent of the polymerization to decrease because of the higher activation energy. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Investigation of chitosan gelation mechanisms by a modeling approach coupled to local experimental measurement
Authors: Venault A. , Bouyer D. , Pochat‐Bohatier C. , Vachoud L. , Faur C. 
Published: July 2011

AbstractThe formation of chitosan hydrogels using experimental and modeling approaches are described. Chitosan gelation was induced by an ammonia intake from a liquid phase (wet process) or a gaseous phase (vapor process), involving three steps: (i) external mass transfer at the interface, (ii) internal transport within the polymer solution, and (iii) chemical reactions inducing gelation. The experimental study allowed quantifying gelation fronts speeds from local measurement. The main resistance to gelation was investigated for both gelation processes. Experimental results exhibited that internal diffusion through the chitosan matrix was the main resistance in the whole gelation mechanism. The numerical model involved a coupling between mass and heat transfer phenomena and chemical reactions, in transient conditions. Numerical results were first validated and then used as a predictive tool to investigate (i) coupled mechanisms localized in the chitosan matrix and (ii) the influence of operating conditions on gelation rates. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Case–control studies for identifying novel teratogens
Authors: Werler Martha M. , Louik Carol , Mitchell Allen A. 
Published: July 2011

AbstractThe case–control study design offers an operationally efficient approach to measuring an association between an exposure and an outcome, especially when the outcome is rare, as is true for specific birth defects. For example, instead of following 50,000 pregnant women to have sufficient statistical power to identify a doubling in risk of oral clefts associated with a common exposure (e.g., cigarette smoking), 75 cases and 3 controls per case could be studied with equal statistical power. Examples of case sources include hospital or clinical series, or birth defect registries. For validity, control subjects should represent the population base of the cases, which can be difficult to identify for non‐population‐based case groups. Case–control studies typically rely on retrospective exposure measurement, which presents a major challenge and sets up the possibility of recall bias. Approaches are discussed to keep sources of bias to a minimum, including recall, non‐differential information, and selection biases. Case–control studies can play an important role in this process for both hypothesis‐generation and hypothesis‐testing of potential teratogens. Examples of case–control studies and their contributions to the field are presented. © 2011 Wiley‐Liss, Inc.
We don't know what we don't study: The case for research on medication effects in pregnancy
Authors: Parisi Melissa A. , Spong Catherine Y. , Zajicek Anne , Guttmacher Alan E. 
Published: July 2011

AbstractThis Commentary addresses issues related to exposures to teratogens and makes the case for increased research into the safety of medication usage during pregnancy for mothers and fetuses. Not only are medications commonly used during pregnancy, but evidence points to an increasing prevalence and number of drug exposures experienced by the embryo or fetus, particularly during the critical first trimester of pregnancy. Although the first trimester represents a particularly vulnerable period of organogenesis, exposures during other gestational time periods may also be associated with deleterious outcomes. In addition to the changing (and in many cases unknown) risks to a developing fetus, other challenges to studying medication exposures and their effects during pregnancy include the dramatic changes in physiology that occur in pregnant women and the ethical dilemmas posed by including this vulnerable population in randomized controlled trials of safety and efficacy. However, without adequate knowledge of the pharmacokinetics, pharmacodynamics, efficacy, and safety of medication use in pregnancy, women may be under‐dosed to minimize exposure or not treated at all, resulting in inadequate treatment and potential harm to the mother and her baby. The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) is undertaking studies on medications and teratogenic exposures during pregnancy, including alcohol, maternal diabetes, oral hypoglycemic agents, and antiviral medications, through several of its research networks. Although this is a start, there is a critical need for further research on medications used during pregnancy, especially their effects on both the mother and her developing child. Published 2011 Wiley‐Liss, Inc.
Evolving knowledge of the teratogenicity of medications in human pregnancy
Authors: Adam Margaret P. , Polifka Janine E. , Friedman J.M. 
Published: July 2011

AbstractA majority of pregnant women take at least one medication during pregnancy, although the safety of such drugs during pregnancy is not always known. We reviewed the safety during pregnancy of 172 drugs approved by the US Food and Drug Administration (FDA) from 2000 to 2010 using the TERIS risk rating system. We also reviewed safety information for 468 drugs approved by the FDA from 1980 to 2000 to determine if revisions in risk categories had been made in the last 10 years. The teratogenic risk in human pregnancy was “undetermined” for 168 (97.7%) of drug treatments approved between 2000 and 2010. Furthermore, the amount of data available regarding safety in pregnancy was rated as “none” for 126 (73.3%) of these drugs. For those drugs approved between 1980 and 2000, only 23 (5%) changed a full risk category or more in the past 10 years. Sources of data that led to a revised risk were derived from exposure cohort studies performed through record linkage studies, teratogen information services, large population‐based case‐control studies, and pregnancy registries. The mean time for a treatment initially classified as having an “undetermined” risk to be assigned a more precise risk was 27 years (95% confidence interval 26–28 years). The lack of information needed to assess the safety of drug treatments during human pregnancy remains a serious public health problem. A more active approach to post‐marketing surveillance for teratogenic effects is necessary. © 2011 Wiley‐Liss, Inc.
Health status among prehistoric Eskimos from Point Hope, Alaska
Authors: Dabbs Gretchen R. 
Published: July 2011

AbstractUsing the protocol outlined in The Backbone of History: Health and Nutrition in the Western Hemisphere (BBH) (Steckel and Rose. 2002a. The backbone of history: health and nutrition in the Western Hemisphere. Cambridge: Cambridge University Press), this project compares the Mark I Health Index (MIHI) scores of the Ipiutak (n = 76; 100BCE–500CE) and Tigara (n = 298; 1200–1700CE), two samples of North American Arctic Eskimos excavated from Point Hope, Alaska. Macroscopic examination of skeletal remains for evidence of anemia, linear enamel hypoplasias (LEH), infection, trauma, dental health, and degenerative joint disease (DJD) was conducted to assess differences in health status resulting from a major economic shift at Point Hope. These data demonstrate that despite differences in settlement pattern, economic system, and dietary composition, the MIHI scores for the Ipiutak (82.1) and Tigara (84.6) are essentially equal. However, their component scores differ considerably. The Ipiutak component scores are suggestive of increased prevalence of chronic metabolic and biomechanical stresses, represented by high prevalence of nonspecific infection and high frequencies of DJD in the hip/knee, thoracic vertebrae, and wrists. The Tigara experienced more acute stress, evidenced by higher prevalence of LEH and trauma. Comparison of overall health index scores with those published in BBH shows the MIHI score for the Ipiutak and Tigara falling just above the average for sites in the Western Hemisphere, adding support to the argument that the human capacity for cultural amelioration of environmental hardships is quite significant. Am J Phys Anthropol, 2011. © 2011 Wiley‐Liss, Inc.
Characterization of soluble and membrane‐bound alkaline phosphatase in Nilaparvata lugens and their potential relation to development and insecticide resistance
Authors: Wang Zengxia , Liu Shuhua , Yang Baojun , Liu Zewen 
Published: July 2011

AbstractTwo forms (soluble and membrane‐bound) of alkaline phosphatases (ALPs) were found in the brown planthopper, Nilaparvata lugens. In order to further study ALPs in N. lugens, two putative ALP genes (Nl‐ALP1 and Nl‐ALP2) were identified in this pest. Both Nl‐ALP1 and Nl‐ALP2 show approximately the same degree of sequence identity (40–50%) to other insect soluble and membrane‐bound forms of ALP. Correlation of ALP activity and mRNA levels at different developmental stages, or following application of 20‐hydroxyecdysone (20E) and insecticide fenvalerate, suggests that Nl‐ALP1 and Nl‐ALP2 might encode a soluble (sALP) and a membrane‐bound ALP (mALP), respectively. Nl‐ALP1‐specific antibody Nl1‐I detected only a specific band in soluble protein preparations and Nl‐ALP2 specific antibody Nl2‐I only detected a specific band in insoluble protein preparations, which provided conclusive linkages between Nl‐ALP1 and a sALP and between Nl‐ALP2 and a m ALP. Then, Nl‐ALP1 was denoted as Nl‐sALP for a sALP and Nl‐ALP2 was denoted as Nl‐mALP for a mALP. Only sALP activity and Nl‐sALP mRNA level were induced by 20E and fenvalerate, which was confirmed by the density of specific band detected by Nl1‐I in Sus strain with or without fenvalerate treatment. Additionally, the sALP activity, as well as Nl‐sALP mRNA level, was significantly higher in a fenvalerate resistant population, compared with Sus strain. These results indicate that the sALP is more responsive to chemical stimulus, such as hormone and insecticide, and might play dual roles in development and insecticide tolerance. © 2011 Wiley Periodicals, Inc.