bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transition‐Metal‐Catalyzed α‐Arylation of Enolates
Authors: Prim Damien , Marque Sylvain , Gaucher Anne , Campagne Jean‐Marc 
Published: March 2012

Abstract
The aim of this chapter is to present an up‐to‐date overview of the transition‐metal‐catalyzed alpha‐arylation of enolates and their derivatives. This chapter discusses the various efforts to develop highly efficient and selective tools for the catalyzed formation of carbon‐carbon and carbon‐heteroatom bonds. Among the latter, outstanding results have been obtained in the field of soft, non‐organometallic nucleophiles. One of the major challenges is the alpha‐arylation of soft carbon nucelophiles such as stabilized carbon enolates and related functional groups. Although alpha‐carboxylic acids and keto derivatives are prevalent in natural products and are important in the building blocks of various drugs (e.g., anti‐inflammatory drugs, anesthetics, etc.), catalytic alpha‐arylation of stabilized carbon enolates has only been recently described. Details on early research is given. More recent developments of this method concern not only the use of a large number of related nucleophiles, but also activated benzylic and vinylogous gamma‐arylations. Current efforts are mainly devoted to multiple arylation sequences, intramolecular alpha‐arylations, and enantioselective alpha‐arylation. Because palladium is the transition metal predominantly employed, the chapter focuses on palladium‐assisted synthetic transformation, However other catalytic systems such as nickel, copper, and ruthenium‐based catalysts are detailed.
Photoacoustic Spectroscopy in Trace Gas Monitoring
Authors: Harren Frans J.M. , Mandon Julien , Cristescu Simona M. 
Published: March 2012

AbstractGas phase spectroscopy is nowadays very common in a wide variety of fields next to chemistry and physics. From research involving living organisms to air pollution monitoring, spectroscopic gas sensors have proven to be indispensable tools. There are various ways of utilizing gas sensors, and each application has different demands. Some applications require a very high sensitivity for one specific gas compound, while others benefit more from sensors able to measure a wide range of gases. A high time resolution is also desirable, as well as selectivity, robustness, and little or no need for sample preparation. This paper discusses photoacoustic spectroscopy as a sensitive, on‐line and non‐invasive tool to monitor the concentration of trace gases. After a short introduction and a historic overview, attention is focused onto the description of devices and equipment; they determine the detection limits and selectivity. Applications are discussed with emphasis on environmental monitoring, medical applications and biological applications (such as post‐harvest physiology, plant physiology, microbiology, and entomology).
Fluorescence Spectroscopy in Food Analysis
Authors: Albani Jihad‐René 
Published: March 2012

AbstractFood is vital for life, thus it is very important to know how to maintain its quality and thus to detect and analyse all components interfering with food quality. This article describes application of spectrofluorometry combined with high‐performance liquid chromatography (HPLC) in food analysis. Spectrofluorometry allows measuring structural changes in food proteins, whereas HPLC combined with fluorescence helps to study toxins, pathogenic microbes, heating effects, fat oxidation, vitamins, additives, amino acids, and enzyme activity in food.
Analytical Platforms in Metabolomics
Authors: Priego‐Capote Feliciano , Luque de Castro María Dolores , Álvarez‐Sánchez Beatriz 
Published: March 2012

AbstractThe present importance of metabolomics to go inside the unsolved secrets of living organisms, as a single discipline or together with other omics, has opened interest in analytical platforms to obtain proper metabolomic information. The steps involved in developing these platforms (viz sampling, sample storage, sample preparation, individual metabolites separation, if required, and detection) are critically discussed as a function of the type of organism under study, the type of sample, and the families of metabolites to be analyzed. An overview of the fundamentals of key equipment in metabolomics, such as that based on nuclear magnetic resonance (NMR) spectrometry or mass spectrometry (MS), is also given for better understanding of its usefulness in this discipline.
Stable Isotope Analysis: General Principles and Limitations
Authors: Meier‐Augenstein Wolfram , Kemp Helen F 
Published: March 2012

AbstractExploiting subtle variations or differences in stable isotope abundance of e.g., drugs, fibres, or human tissue is an emerging and innovative tool for forensic chemical analysis. This article provides an introduction into stable isotope analysis, stable isotope terminology, and how isotope ratio measurements are quality controlled, while at the same time putting the information contained in stable isotope signatures into a forensic context.
Genetic Modifier Screens in Mice
Authors: Carpinelli Marina R. , Burt Rachel A. , Kile Benjamin T. 
Published: March 2012

AbstractENU mutagenesis is a forward genetics strategy in which random mutagenesis and phenotypic screening is used to identify genes based on the phenotype induced when they are mutated. A modifier screen is a type of screen in which mice with a pre‐existing phenotype are utilized to identify mutations that can enhance or suppress this phenotype. This approach has the potential to uncover missing pathway members, reveal novel genetic interactions, and pinpoint new drug targets. Considerations when planning a suppressor screen include current knowledge, genomic footprint, penetrance, variance, robustness, latency of the starting phenotype, viability, fertility, genetic background and ENU tolerance of starting strain, screening assay, mouse numbers required, and mutation identification strategy. Practical advice on each of these is provided in this review. Curr. Protoc. Mouse Biol. 2:75‐87 © 2012 by John Wiley & Sons, Inc.
Antibacterial Surface Coatings from Zinc Oxide Nanoparticles Embedded in Poly(N‐isopropylacrylamide) Hydrogel Surface Layers
Authors: Schwartz Véronique B. , Thétiot Franck , Ritz Sandra , Pütz Sabine , Choritz Lars , Lappas Alexandros , Förch Renate , Landfester Katharina , Jonas Ulrich 
Published: March 2012

AbstractDespite multiple research approaches to prevent bacterial colonization on surfaces, device‐associated infections are currently responsible for about 50% of nosocomial infections in Europe and significantly increase health care costs, which demands development of advanced antibacterial surface coatings. Here, novel antimicrobial composite materials incorporating zinc oxide nanoparticles (ZnO NP) into biocompatible poly(N‐isopropylacrylamide) (PNIPAAm) hydrogel layers are prepared by mixing the PNIPAAm prepolymer with ZnO NP, followed by spin‐coating and photocrosslinking. Scanning electron microscopy (SEM) characterization of the composite film morphology reveals a homogeneous distribution of the ZnO NP throughout the film for every applied NP/polymer ratio. The optical properties of the embedded NP are not affected by the matrix as confirmed by UV‐vis spectroscopy. The nanocomposite films exhibit bactericidal behavior towards Escherichia coli (E. coli) for a ZnO concentration as low as ≈0.74 μg cm−2 (1.33 mmol cm−3), which is determined by inductively coupled plasma optical emission spectrometry. In contrast, the coatings are found to be non‐cytotoxic towards a mammalian cell line (NIH/3T3) at bactericidal loadings of ZnO over an extended period of seven days. The differential toxicity of the ZnO/hydrogel nanocomposite thin films between bacterial and cellular species qualifies them as promising candidates for novel biomedical device coatings.
Ultrasmall Water‐Soluble and Biocompatible Magnetic Iron Oxide Nanoparticles as Positive and Negative Dual Contrast Agents
Authors: Li Zhen , Yi Pei Wei , Sun Qiao , Lei Hao , Li Zhao Hong , Zhu Zhong Hua , Smith Sean C. , Lan Min Bo , Lu Gao Qing (Max) 
Published: March 2012

AbstractMonodispersed water‐soluble and biocompatible ultrasmall magnetic iron oxide nanoparticles (UMIONs, D = 3.3 ± 0.5 nm) generated from a high‐temperature coprecipitation route are successfully used as efficient positive and negative dual contrast agents of magnetic resonance imaging (MRI). Their longitudinal relaxivity at 4.7 T (r1 = 8.3 mM−1 s−1) is larger than that of clinically used T1‐positive agent Gd‐DTPA (r1 = 4.8 mM−1 s−1), and three times that of commercial contrast agent SHU‐555C (r1 = 2.9 mM−1 s−1). The transversal relaxivity (r2 = 35.1 mM−1 s−1) is six times that of Gd‐DTPA (r2 = 5.3 mM−1 s−1), half of SHU‐555C (r2 = 69 mM−1 s−1). The in vivo results show that the liver signal from T1‐weighted MRI is positively enhanced 26%, and then negatively decreased 20% after injection of the iron oxide nanoparticles, which is stronger than those obtained from Gd‐DTPA (<10%) using the same dosage. The kidney signal is positively enhanced up to 35%, similar to that obtained from Gd‐DTPA. Under T2‐weighted conditions, the liver signal is negatively enhanced ≅70%, which is significantly higher than that from Gd‐DTPA (≅6%). These results demonstrate the great potential of the UMIONs in dual contrast agents, especially as an alternative to Gd‐based positive contrast agents, which have risks of inducing side effects in patients.
Laboratory and field methods for measuring human energy expenditure
Authors: Leonard William R. 
Published: March 2012

AbstractEnergetics research is central to the field of human biology. Energy is an important currency for measuring adaptation, because both its acquisition and allocation for biological processes have important implications for survival and reproduction. Recent technological and methodological advances are now allowing human biologists to study variation in energy dynamics with much greater accuracy in a wide variety of ecological contexts. This article provides an overview of the methods used for measuring human energy expenditure (EE) and considers some of the important ecological and evolutionary questions that can be explored from an energetics perspective. Basic principles of calorimetry are first presented, followed by an overview of the equipment used for measuring human EE and work capacity. Methods for measuring three important dimensions of human EE—resting metabolic rate, working/exercising EE, and total EE—are then presented, highlighting key areas of ongoing research. Am. J. Hum. Biol. 2012. © 2012 Wiley Periodicals, Inc.
Transition analysis: A validation study with known‐age modern American skeletons
Authors: Milner George R. , Boldsen Jesper L. 
Published: March 2012

AbstractTransition Analysis—a recent skeletal age‐estimation procedure (Boldsen et al.: Paleodemography: age distributions from skeletal samples (2002) 73–106)—is evaluated using 252 known‐age modern American males and females from the Bass Donated Collection and Mercyhurst forensic cases. The pubic symphysis worked best for estimating age, followed by the sacroiliac joint and cranial sutures. Estimates based on all skeletal characteristics are influenced by the choice of prior distribution, although its effect is dwarfed by both the inaccuracy and imprecision of age estimates. Age intervals are narrowest for young adults, but are surprisingly short in old age as well. When using an informative prior distribution, the greatest uncertainty occurs from the late 40s into the 70s. Transition Analysis estimates do not perform as well as experience‐based assessments, indicating the existing procedure is too narrowly focused on commonly used pelvic and cranial structures. Am J Phys Anthropol, 2012. © 2012 Wiley Periodicals, Inc.
Placement of the diaphragmatic vertebra in catarrhines: Implications for the evolution of dorsostability in hominoids and bipedalism in hominins
Authors: Williams Scott A. 
Published: March 2012

AbstractA fundamental adaptation to orthograde posture and locomotion amongst living hominoid primates is a numerically reduced lumbar column, which acts to stiffen the lower back and reduce injuries to the intervertebral discs. A related and functionally complementary strategy of spinal stability is a caudal position of the diaphragmatic vertebra relative to the primitive condition found in nonhominoid primates and most other mammals. The diaphragmatic vertebra marks the transition in vertebral articular facet (zygapophysis) orientation, which either resists (prediaphragmatic) or allows (postdiaphragmatic) trunk movement in the sagittal plane (i.e., flexion and extension). Unlike most mammals, which have dorsomobile spines (long lumbar columns and cranially placed diaphragmatic vertebrae) for running and leaping, hominoids possess dorsostable spines (short lumbar columns and caudally placed diaphragmatic vertebrae) adapted to orthogrady and antipronogrady. In contrast to humans and other extant hominoids, all known early hominin partial vertebral columns demonstrate cranial displacement of the diaphragmatic vertebra. To address this difference, variation in diaphragmatic placement is assessed in a large sample of catarrhine primates. I show that while hominoids are characterized by modal common placement of diaphragmatic and last rib‐bearing vertebrae in general, interspecific differences in intraspecific patterns of variation exist. In particular, humans and chimpanzees show nearly identical patterns of diaphragmatic placement. A scenario of hominin evolution is proposed in which early hominins evolved cranial displacement from the ancestral hominid condition of common placement to achieve effective lumbar lordosis during the evolution of bipedal locomotion. Am J Phys Anthropol, 2012. © 2012 Wiley Periodicals, Inc.
Preparation and characterization of electrospun polyurethane–polypyrrole nanofibers and films
Authors: Yanilmaz Meltem , Kalaoglu Fatma , Karakas Hale , Sarac A. Sezai 
Published: March 2012

AbstractPolyurethane (PU)–polypyrrole (PPy) composite films and nanofibers were successfully prepared for the purpose of combining the properties of PU and PPy. Pyrrole (Py) monomer was polymerized and dispersed uniformly throughout the PU matrix by means of oxidative polymerization with cerium(IV) [ceric ammonium nitrate Ce(IV)] in dimethylformamide. Films and nanofibers were prepared with this solution. The effects of the PPy content on the thermal, mechanical, dielectric, and morphological properties of the composites were investigated with differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), Fourier transform infrared (FTIR)–attenuated total reflection (ATR) spectroscopy, dielectric spectrometry, and scanning electron microscopy. The Young's modulus and glass‐transition temperatures of the composites exhibited an increasing trend with increases in the initially added amount of Py. The electrical conductivities of the composite films and nanofibers increased. The crystallinity of the composites were followed with DSC, the mechanical properties were followed with DMA, and the spectroscopic results were followed with FTIR–ATR spectroscopy. In the composite films, a new absorption band located at about 1650 cm−1 appeared, and its intensity improved with the addition of Py. The studied composites show potential for promising applications in advanced electronic devices. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and properties of starch‐grafted polystyrene‐maleic anhydride copolymer
Authors: Chen Guang‐Xin , Geng Haiping , Luo Lingling , Wu Bin , Fang Li Qi 
Published: March 2012

AbstractThe typical process used to synthesize expandable polystyrene was modified and applied to prepare water expandable polystyrene (WEPS)‐starch copolymer. The maleic anhydride was used to improve the compatibility between starch and styrene. Various reaction conditions, weight ratio of styrene/water (O/W ratio), and starch content, were applied to obtain WEPS copolymer beads. Molecular weight, molecular weight distribution, glass transition temperature (Tg), and phase behavior of copolymer were investigated. With the increase of O/W ratio, the water content and molecular weight increased, whereas the molecular weight distribution and Tg of copolymer decreased. Molecular weight distribution and the Tg of the copolymer both increased as a function of starch content. The water content in the beads reached the maximum value at 6 wt % of starch content at same O/W ratio. The domain size of starch increased with the increase of the starch content. The domain size distribution of starch was best at 6 wt % of starch. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Improved Regeneration of Autologous Transplanted Lymph Node Fragments by VEGF‐C Treatment
Authors: Sommer Tanja , Buettner Manuela , Bruns Frank , Breves Gerhard , Hadamitzky Catarina , Pabst Reinhard 
Published: March 2012

AbstractSecondary lymphedema is a common complication after removal of lymph nodes in combination with radiation therapy in the treatment of breast cancer, cervical cancer, and melanomas. Only symptomatic therapies are available at the moment, and lymphedema is for most patients a lifelong condition involving psychological and physical disabilities. Animal models exist to study the pathophysiology of lymphedema but not to study surgical treatments. The aim of this study was to show that regeneration of autologous transplanted lymph node fragments is possible in rats that were irradiated previously locally in the groin and to examine the effects of vascular endothelial growth factor (VEGF)‐C injections on the rate of regeneration of transplanted lymph nodes. In all of the animals, inguinal and popliteal lymph nodes and adjacent lymphatic vessels were unilaterally removed and the inguinal region irradiated by a single dose of 15 Gy. Afterward, lymph node fragments were transplanted subcutaneously in the irradiated region. Half of the animals were treated by local VEGF‐C injections after transplantation. Four weeks after transplantation, drainage of the leg was tested by injection of blue dye, and the transplanted fragments were removed and examined immunohistologically. We could show that regeneration of autologous transplanted lymph node fragments is possible in areas treated with radiotherapy in the rat. We also documented that transplants can achieve a connection to the lymphatic collectors of the leg. The results suggest that the outcome of regeneration can be improved by injection of VEGF‐C in the transplantation area. Thus, lymph node fragment regeneration may be relevant for lymphedema prevention and therapy. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Temperature‐Dependent Formation and Transformation of Mesostructures in Water–Ionic Liquid Mixtures
Authors: Kattnig Daniel R. , Hinderberger Dariush 
Published: March 2012

AbstractThe temperature‐dependent formation and transformation of mesostructures in binary mixtures of the ionic liquid (IL) 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([bmim+][BF4−]) and water are characterized. Through addition of nitroxide radicals as paramagnetic spin probes, the temperature dependence of the solution structure can be assessed by using electron paramagnetic resonance (EPR) spectroscopy from typical solutes’ points of view. Additionally, the phase behavior on cooling and reheating is probed by differential scanning calorimetry (DSC). Thermal hysteresis and memory effects are observed, and DSC is used to identify the crystallization and thawing of ice as the pertinent phase transition. The EPR data of the nitroxide radicals before and after freezing and thawing reveal a transformation of the mesostructures, probably triggered by the crystallization of water pools to ice. A more polar state results after thawing, thereby suggesting a rupture and dissolution of the ordered IL‐rich mesostructures. If the thawed solutions are not agitated, the system relaxes very slowly, that is, at room temperature with a time constant of approximately 90 h, to its equilibrium state of mesophase‐separated IL‐rich and bulk‐like water regions.
Improvements to a prognostic cloud scheme through changes to its cloud erosion parametrization
Authors: Morcrette Cyril J. 
Published: March 2012

AbstractA cloud erosion parametrization is developed for use in a prognostic cloud scheme in a general circulation model. Using geometrical considerations, the rate of evaporation of cloud due to unresolved mixing of clear and cloudy air is related to the cloud fraction, in a way that maximizes evaporation when the sky is half covered in cloud and reduces it to zero when the sky is overcast or clear. When used to simulate present‐day climate with the Met Office Unified Model, this parametrization leads to several improvements in the cloud and radiation fields. © 2012 British Crown copyright, the Met Office. Published by John Wiley & Sons Ltd.
Impact of probability of working day on planning and operation of biomass feedstock production systems
Authors: Shastri Yogendra N. , Hansen Alan C. , Rodríguez Luis F. , Ting K.C. 
Published: March 2012

AbstractUnfavorable weather can significantly impact the production and provision of agriculture‐based biomass feedstocks such as Miscanthus and switchgrass. This work quantified the impact of regional weather on the feedstock production systems using the BioFeed modeling framework. Weather effects were incorporated in BioFeed by including the probability of working day (pwd) parameter in the model, which defined the fraction of days in a specific period such as two weeks that were suitable for field operations. Model simulations were conducted for Miscanthus and switchgrass for values of pwd between 20 and 100% and intended biorefinery capacities between 1000 and 5000 Mg d−1; and the impact on total cost and farm machinery requirements was quantified. Results indicated that using production and provision systems designed assuming 100% pwd for lower pwd values increased the cost exponentially by up to 64% for Miscanthus and 85% for switchgrass. It also decreased the supportable biorefinery capacity for the collection region by up to 60%. If the systems were instead optimized for specific values of pwd, the original biorefinery capacity was maintained and the total cost increase was less than 5%. The resulting optimal systems required up to 40% higher investment in farm machinery. For Illinois, production systems designed for regional pwd values required a 34% increase in farm machinery investment for Miscanthus while only a 12% increase for switchgrass. Initiating Miscanthus harvesting in November instead of January reduced the farm machinery investment increase to 17%, which suggests that such an alternative should be rigorously evaluated. © 2012 Society of Chemical Industry and John Wiley & Sons, Ltd
Somatic cell reprogramming for regenerative medicine: SCNT vs. iPS cells
Authors: Pan Guangjin , Wang Tao , Yao Hongjie , Pei Duanqing 
Published: March 2012

AbstractReprogramming of somatic cells to a pluripotent state holds huge potentials for regenerative medicine. However, a debate over which method is better, somatic cell nuclear transfer (SCNT) or induced pluripotent stem (iPS) cells, still persists. Both approaches have the potential to generate patient‐specific pluripotent stem cells for replacement therapy. Yet, although SCNT has been successfully applied in various vertebrates, no human pluripotent stem cells have been generated by SCNT due to technical, legal and ethical difficulties. On the other hand, human iPS cell lines have been reported from both healthy and diseased individuals. A recent study reported the generation of triploid human pluripotent stem cells by transferring somatic nuclei into oocytes, a variant form of SCNT. In this essay, we discuss this progress and the potentials of these two reprogramming approaches for regenerative medicine.