bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Photophysics of a New Family of Fluorescent 9‐Alkyl‐Substituted Xanthenones
Authors: Martínez‐Peragón Ángela , Miguel Delia , Jurado Rocío , Justicia José , Álvarez‐Pez José M. , Cuerva Juan M. , Crovetto Luis 
Published: November 2013

Abstract9‐Alkyl xanthenones with different aliphatic pendant groups have been easily prepared by means of nucleophilic addition of the corresponding Grignard derivative to a tert‐butyldimethylsilyl ether (TBDMS)‐protected 3,6‐dihydroxy‐xanthenone. The photophysical behavior of the new dyes has been explored by using absorption, steady‐state‐, and time‐resolved fluorescence measurements. We determined the equilibrium constants, visible spectral characteristics, fluorescence quantum yield, and decay times. Remarkably, they retain similar fluorescent properties of fluorescein including the characteristic phosphate‐mediated excited‐state proton‐transfer (ESPT) reaction. 6‐Hydroxy‐9‐isopropyl‐3H‐xanthen‐3‐one (5) was investigated in living cells; it presented a good permeability and efficient accumulation inside the cytosol. For the first time, we reported that the requirement of an aryl group at C‐9 is no longer needed and new fluorescent sensors can be therefore easily developed.
Asymmetric α‐Hydroxylation of a Lactone with Vinylogous Pyridone by Using a Guanidine–Urea Bifunctional Organocatalyst: Catalytic Enantioselective Synthesis of a Key Intermediate for (20S)‐Camptothecin Analogues
Authors: Watanabe Tatsuya , Odagi Minami , Furukori Kota , Nagasawa Kazuo 
Published: November 2013

AbstractWe have developed a catalytic asymmetric synthesis of (S)‐4‐ethyl‐6,6‐(ethylenedioxy)‐7,8‐dihydro‐4‐hydroxy‐1H‐pyrano[3,4‐f]indolizine‐3,10(4H)dione (5 a), a synthetic intermediate for (20S)‐camptothecin analogues. A key step in this synthesis is an asymmetric α‐hydroxylation of a lactone with a vinylogous pyridone structure (8 a) by using a guanidine–urea bifunctional organocatalyst. The present oxidation was successfully applied to the synthesis of C20‐modified derivatives of (+)‐C20‐desethylbenzylcamptothecin (13).
Performance Evaluation of Protective Clothing Against Toxic Industrial Chemicals
Authors: Fernández José Francisco , Nierobisch Paul , Niemeyer Bernd 
Published: November 2013

AbstractThere are two possible solutions to avoid skin resorption of toxic industrial chemicals (TIC). An impermeable overgarment provides effective and reasonable protection, but it is naturally not breathable and presupposes physical stress for the wearer and thus limited work capabilities. In contrast, a semipermeable overgarment containing an adsorption layer currently based on activated carbon is more suitable, because it allows the transfer of corporal heat and dissipates perspiration from the skin. However, it cannot provide the same level of protection against all kinds of TIC. Consequently, an evaluation of the performance of a commercially available overgarment is presented in this study.
Palladacycle‐Catalyzed Carbonylation of Aryl Iodides or Bromides with Aryl Formates
Authors: Chen Guangwei , Leng Yuting , Yang Fan , Wang Shiwei , Wu Yangjie 
Published: November 2013

AbstractAn efficient palladacycle‐catalyzed aromatic carbonylation reaction of aryl formates with aryl iodides or bromides has been developed. Commercially available and easily prepared aryl formates were employed as carbonyl sources without the use of external carbon monoxide. The present catalytic system shows broad functional group tolerance and affords aryl benzoate derivatives in good to excellent yields.
Supramolecular Micelles and Reverse Micelles Based on Cyclodextrin Polyrotaxanes
Authors: Jin Qiao , Liu Gongyan , Ji Jian 
Published: November 2013

AbstractA new supramolecular self‐assembly approach to construct micelles and reverse micelles was reported. Double‐hydrophilic block copolymers poly(ethylene oxide)‐b‐poly(N‐isopropylacrylamide) (PEO‐b‐PNIPAAm) was synthesized via atom transfer radical polymerization (ATRP) using PEO macroinitiator. Because of the lower critical solution temperature (LCST) phase behavior of PNIPAAm, PEO‐b‐PNIPAAm block copolymers self‐assembled to form PNIPAAm‐core micelles at 40°C. The PNIPAAm‐core micelles were disassembled to unimers when the temperature was decreased to 25°C. But the addition of α‐cyclodextrins (α‐CDs) could induce the formation of PNIPAAm‐shell micelles because of the "channel‐type" crystallities induced by PEO/α‐CDs polyrotaxanes. The assembly and disassembly procedure of micelles and reverse micelles were investigated by dynamic light scattering (DLS), X‐ray diffraction (XRD), 1H NMR and transmission electron microscopy (TEM).
I spy with my little eye: Typical, daily exposure to faces documented from a first‐person infant perspective
Authors: Sugden Nicole A. , Mohamed‐Ali Marwan I. , Moulson Margaret C. 
Published: November 2013

ABSTRACTExposure to faces is known to shape and change the face processing system; however, no study has yet documented infants' natural daily first‐hand exposure to faces. One‐ and three‐month‐old infants' visual experience was recorded through head‐mounted cameras. The video recordings were coded for faces to determine: (1) How often are infants exposed to faces? (2) To what type of faces are they exposed? and (3) Do frequently encountered face types reflect infants' typical pattern of perceptual narrowing? As hypothesized, infants spent a large proportion of their time (25%) exposed to faces; these faces were primarily female (70%), own‐race (96%), and adult‐age (81%). Infants were exposed to more individual exemplars of female, own‐race, and adult‐age faces than to male, other‐race, and child‐ or older‐adult‐age faces. Each exposure to own‐race faces was longer than to other‐race faces. There were no differences in exposure duration related to the gender or age of the face. Previous research has found that the face types frequently experienced by our participants are preferred over and more successfully recognized than other face types. The patterns of face exposure revealed in the current study coincide with the known trajectory of perceptual narrowing seen later in infancy.© 2013 The Authors. Developmental Psychobiology Published by Wiley Periodicals, Inc. Dev Psychobiol 56: 249–261, 2014.
Birth, survival and differentiation of neurons in an adult crustacean brain
Authors: Kim Youngmi Faith , Sandeman David C. , Benton Jeanne L. , Beltz Barbara S. 
Published: November 2013

AbstractLife‐long neurogenesis is a characteristic feature of many vertebrate and invertebrate species. In decapod crustaceans, new neurons are added throughout life to two cell clusters containing local (cluster 9) and projection (cluster 10) interneurons in the olfactory pathway. Adult‐born neurons in clusters 9 and 10 in crayfish have the anatomical properties and chemistry of mature neurons by 6 months after birth. Here we use 5‐bromo‐2′‐deoxyuridine (BrdU) incorporation to pulse label mitotically active cells in these cell clusters, followed by a survival time of up to 8 months, during which crayfish (Cherax destructor) were sacrificed at intervals and the numbers of BrdU‐labeled cells quantified. We find a decrease in the numbers of BrdU‐labeled cells in cell cluster 10 between the first and second weeks following BrdU exposure, suggesting a period of cell death shortly after proliferation. Additional delayed cell divisions in both cell clusters are indicated by increases in labeled cells long after the BrdU clearing time. The differentiation time of these cells into neurons was defined by detection of the first immunoreactivity for the transmitter SIFamide in cluster 10 BrdU‐labeled cells, which begins at 4 weeks after BrdU labeling; the numbers of SIFamide‐labeled cells continues to increase over the following month. Experiments testing whether proliferation and survival of Cluster 10 cells are influenced by locomotor activity provided no evidence of a correlation between activity levels and cell proliferation, but suggest a strong influence of locomotor activity on cell survival. © 2013 Wiley Periodicals, Inc. Develop Neurobiol 74: 602–615, 2014
Lanthanoid Tetramethylaluminates and Their Paramagnetic NMR Parameters
Authors: Nieland Anja , Mix Andreas , Neumann Beate , Stammler Hans‐Georg , Mitzel Norbert W. 
Published: November 2013

AbstractTris(tetramethylaluminate)s of the lanthanoids cerium (1), holmium (2), and erbium (3) were synthesized by treating lanthanoid amide complexes of the type [Ln(NMe2)3(LiCl)3] with an excess amount of AlMe3. These compounds were characterized by single‐crystal X‐ray diffraction, elemental analysis, and NMR spectroscopy. Paramagnetic NMR spectroscopic studies were undertaken to investigate the influence of the compounds on the solvent chemical shifts. NMR parameters for the 1H, 13C, and 27Al nuclei of all the reported lanthanoid tris(tetramethylaluminate)s were measured. The reactions of tris(tetramethylaluminate)s of samarium and holmium with an excess amount of tetrahydrofuran led to [LnMe2(thf)5][AlMe4] {Ln = Ho (4), Sm (5)}. NMR spectroscopic investigations of the paramagnetic holmium and samarium methyl compounds (i.e., 4, 5) as well as the known diamagnetic analogue [YMe2(thf)5][AlMe4] revealed methyl group exchange processes in solution.
Coordination Behaviour of a Hexadentate 1,1′‐Ferrocenylene‐Bridged Bisphosphole towards Coinage Metal Centres
Authors: Orthaber Andreas , Borucki Stefan , Shen Wenting , Réau Regis , Lescop Christophe , Pietschnig Rudolf 
Published: November 2013

AbstractWe describe the synthesis of a ferrocenylene‐bridged bis[2,5‐bis(2‐pyridyl)]phosphole ligand that shows additional rotational degrees of freedom relative to its previously described p‐phenylene‐bridged congener. The coordination behaviour of this ferrocenylene‐based bis‐N,P,N pincer towards coinage metal centres MI with M = Cu and Au was explored, revealing different coordination modes with and without involvement of N donation. Upon coordination of AuI metal centres, different isomers of a bimetallic AuI complex were isolated in the crystalline solid state that showed (or did not) intramolecular aurophilic interaction. Aurophilic as well as Au–N interactions have been investigated by means of ab initio calculations.
Late‐Stage β‐Epimerization. A Stereodivergent to Stereoconvergent Relay to the First Total Synthesis of (+)‐Murolic Acid
Authors: Fernandes Rodney A. , Patil Pradnya H. , Chowdhury Asim K. 
Published: November 2013

AbstractThe first total synthesis of (+)‐murolic acid is accomplished in 17 steps from ester 9 in 14.8 % overall yield. The key steps involve asymmetric dihydroxylation, orthoester Johnson–Claisen rearrangement and α‐methylenation using Stiles reagent. A beneficial late stage β‐epimerization reverted a stereodivergent relay to a stereoconvergent completion of an efficient synthesis of (+)‐murolic acid.
Influence of sodium chloride on hydrophobic adsorption of PEGylated lysozyme
Authors: Werner Albert , Blaschke Tim , Hasse Hans 
Published: November 2013

Interaction of macromolecules in aqueous salt‐containing solution with a hydrophobic adsorbent is studied by adsorption equilibrium measurements and by independent isothermal titration calorimetry. The macromolecules are native as well as mono‐, di‐, and tri‐PEGylated lysozyme and four pure PEGs. The hydrophobic adsorbent is Toyopearl PPG‐600M. The salt is sodium chloride. The sodium chloride concentration in the aqueous 25 mM sodium phosphate buffer is varied from 2000 to 4500 mM at pH 7.0 and 25°C. PEGylation of the lysozyme is carried using 5 and 10 kDa PEG chains. The molar enthalpy of adsorption is calculated from the adsorption equilibrium and the calorimetric data. The results show that the adsorption of the PEGylated lysozyme is caused by both the interaction of the lysozyme and the interaction of the PEG chains with the adsorbent, respectively, but the interaction of the lysozyme is stronger than that of PEG. The comparison of the results of the present study on the influence of sodium chloride with a corresponding study on the influence of ammonium sulfate shows that the adsorption mechanism changes upon the variation of the salt. The knowledge of the adsorption mechanisms supports the systematic development of chromatographic purification steps.
Salinity influences on the uptake of silver nanoparticles and silver nitrate by marine medaka (Oryzias melastigma)
Authors: Wang Jian , Wang Wen-xiong 
Published: November 2013

Abstract

With increasing use of silver nanoparticles (AgNPs), concerns about their potential deleterious effects on aquatic ecosystems have increased. Most previous studies have focused on the toxicity of AgNPs while their bioavailability has been seldom investigated. The present study examined the effects of salinity on the aggregation kinetics as well as the bioavailability of commercial 80-nm citrate-coated AgNPs (c-AgNPs) in the presence or absence of a nonionic surfactant (Tween 20) to marine medaka (Oryzias melastigma). In addition, the uptake of soluble Ag was quantified for comparison and for deducting the uptake of soluble Ag during AgNP exposure by applying a biokinetic model. The authors found that the addition of Tween 20 immediately slowed down the process of aggregation of AgNPs, and an elevated amount of Tween 20 (20 µM) kept AgNPs well dispersed, even in the 30-psu salinity medium. Uptake rate constants (ku) of AgNPs were less than half the soluble Ag at low salinities (1 psu and 5 psu), while limited bioavailability of c-AgNPs was observed at high salinities (15 psu and 30 psu). However, the Tween 20–stabilized AgNPs (t-AgNPs) were accumulated by medaka at comparable rates as the soluble Ag, indicating the importance of dispersion for bioavailability of AgNPs in a highly ionic environment. The present study provided the first insight of the bioavailability of AgNPs to fish in a high-ionic environment. More studies are needed to gain a full understanding of bioavailability of AgNPs in marine environments. Environ Toxicol Chem 2014;33:632–640. © 2013 SETAC
Impact of imidacloprid on Daphnia magna under different food quality regimes
Authors: Ieromina Oleksandra , Peijnenburg Willie J.G.M. , de Snoo Geert , Müller Jutta , Knepper Thomas P. , Vijver Martina G. 
Published: November 2013

Abstract

Aquatic ecosystems are characterized by fluctuating conditions that have direct effects on aquatic communities but also indirect influences such as changing the toxicity of chemicals. Because the effect of food quality on pesticide toxicity has rarely been studied, in the present study Daphnia magna juveniles supplied with 4 different food quality levels were exposed to a range of imidacloprid concentrations for 21 d. Food quality was expressed as carbon:phosphorus ratios of algae Pseudokirchneriella subcapitata (C:P 35, C:P 240, C:P 400, and C:P 1300). Survival, growth rates, and reproduction of D. magna were monitored, and the combined effects of imidacloprid exposure and the phosphorus content of algae were analyzed. A stronger effect on survival was observed at the P-deficient diet (C:P 1300), confirmed by lower 10% effect concentration (EC10) values at days 7, 9, 15, and 21 compared with diets with higher phosphorus contents. Similarly, the growth rate was reduced when D. magna were supplied with algae of low phosphorus content at imidacloprid exposure conditions. The highest reproductive output was observed for D. magna fed the optimal phosphorus diet (C:P 240), both at control and exposed conditions. Poor food quality increased the sensitivity of nontarget species to pesticide exposure, potentially leading to an underestimation of adverse effects on aquatic communities in the field. Environ Toxicol Chem 2014;33:621–631. © 2013 SETAC
Algal growth stimulation and toxicity in response to exposure to the new insensitive military high-nitrogen energetic triaminoguanidinium-1-methyl-5-nitriminotetrazolate
Authors: Stanley Jacob K. , Biedenbach James M. , Russell Amber L. , Bednar Anthony J. 
Published: November 2013

Abstract

Triaminoguanidinium-1-methyl-5-nitriminotetrazolate (TAG-MNT) is a nitrogen-rich energetic compound being developed as a potential component of insensitive munition formulations. The purpose of the present study was to assess the toxicity of TAG-MNT to the green alga Pseudokirchneriella subcapitata as well as to determine whether the high N content of TAG-MNT could result in increased algal growth in aquatic systems and potentially contribute to eutrophication using a 96-h algal growth bioassay in N-limited test media. Results were compared with algal exposures to current-use energetics 2,4,6-trinitrotoluene (TNT) and royal demolition explosive (RDX). The TNT exposure resulted in a lowest-observed-adverse-effect concentration (LOAEC) for algal growth of 1.72 mg/L and a 50% inhibition concentration (IC50) and 95% confidence limits of 0.972 mg/L (0.955, 0.973). The RDX algal growth LOAEC was 0.10 mg/L, and the RDX IC50 was 0.635 (0.416, 0.875). Neither TNT nor RDX exposure resulted in stimulation of algal growth. In repeated testing, TAG-MNT exposure resulted in LOAECs of 0.55 and 5.20 mg/L. Stimulation of algal growth was observed at 0.06 mg/L at a mean increase of 163.2% (± 71.7) relative to the control in TAG-MNT test A and at the 0.005 mg/L treatment at a mean increase of 174.3% (± 59.9) in TAG-MNT test B. The authors' results indicate the potential for high-N energetics to significantly stimulate algal growth at low concentrations in N-limited systems. Environ Toxicol Chem 2014;33:616–620. © 2013 SETAC. This article is a US Government work and is in the public domain in the USA.
Sorption and desorption of alcohol sulfate surfactants in an agricultural soil
Authors: Fernández-Ramos Carolina , Ballesteros Oscar , Zafra-Gómez Alberto , Blanc-García Rosario , Navalón Alberto , Crovetto Sara Isabel , Oliver-Rodríguez Bartolomé , García-Delgado Rafael Antonio , Vílchez José Luís 
Published: November 2013

Abstract

Alcohol sulfates are one of the most important types of commercial anionic surfactants and may pose serious environmental problems. The present study examines the sorption behavior of alcohol sulfates in an agricultural soil using a batch reactor and column experiments. Kinetics and equilibrium isotherms of the sorption and desorption processes of the following alcohol sulfate homologues have been determined: AS-C12, AS-C14, AS-C16, and AS-C18. Sorption and desorption occurred rapidly, and equilibrium was achieved in approximately 1 h. The sorbed mass percentages were 35.1% AS-C12, 67.2% AS-C14, and 100% for both AS-C16 and AS-C18. A pseudo–first-order kinetic model provided an adequate fit of data. Sorption and desorption equilibrium data were fitted into 1) a linear model, with r2 values in the ranges 0.712 to 0.988 and 0.736 to 0.983, respectively, and 2) a Freundlich model, with r2 values in the ranges 0.956 to 0.991 and 0.891 to 0.981, respectively. Continuous-flow experiments in soil columns were carried out to obtain the breakthrough curves for each compound. The present study provides basic theoretical concepts and key parameters for developing mathematical models that simulate the migration of alcohol sulfate into agricultural soils. Environ Toxicol Chem 2014;33:508–515. © 2013 SETAC
Interactive effects of lambda-cyhalothrin, soil moisture, and temperature on Folsomia candida and Sinella curviseta (Collembola)
Authors: Bandow Cornelia , Coors Anja , Karau Nora , Römbke Jörg 
Published: November 2013

Abstract

The authors investigated whether and how 2 environmental factors could influence the toxicity of a pyrethroid to 2 representatives of an important group of soil organisms. The impacts of different temperatures (20 °C and 26 °C) and soil moisture levels (30%, 50%, and 70% of water holding capacity) were investigated in combination with the insecticide lambda-cyhalothrin on the reproduction success of Folsomia candida and Sinella curviseta in a full factorial design. Testing was based on the standard collembolan reproduction test (Organisation for Economic Co-operation and Development, guideline 232) following an effect concentration design. The results showed an effect of environmental and chemical factors on the number of juveniles of these animals. Particularly in dry soil, the reproduction of both species was reduced, while higher soil moisture levels influenced the number of juveniles positively compared with the middle soil moisture level. In general, however, higher soil moisture led to increased sensitivity to lambda-cyhalothrin. In both organisms, temperature affected the toxicity of the pesticide but in different directions: high temperature led to higher toxicity in F. candida but to lower toxicity in S. curviseta. Environ Toxicol Chem 2014;33:654–661. © 2013 SETAC
A semi‐implicit numerical method for the free‐surface Navier–Stokes equations
Authors: Casulli Vincenzo 
Published: November 2013

SUMMARYSemi‐implicit methods are known for being the basis of simple, efficient, accurate, and stable numerical algorithms for simulating a large variety of geophysical free‐surface flows. Geophysical flows are typically characterized by having a small vertical scale as compared with their horizontal extents. Hence, the hydrostatic approximation often applies, and the free surface can be conveniently represented by a single‐valued function of the horizontal coordinates. In the present investigation, semi‐implicit methods are extended to complex free‐surface flows that are governed by the full incompressible Navier–Stokes equations and are delimited by solid boundaries and arbitrarily shaped free‐surfaces. The primary dependent variables are the velocity components and the pressure. Finite difference equations for momentum, and a finite volume discretization for continuity, are derived in such a fashion that, after simple manipulation, the resulting pressure equation yields a well‐posed piecewise linear system from which both the pressure and the fluid volume within each computational cell are naturally derived. This system is efficiently solved by a nested Newton type iterative scheme, and the resulting fluid volumes are assured to be nonnegative and bounded from above by the available cell volumes. The time step size is not restricted by stability conditions dictated by surface wave speed, but can be freely chosen just to achieve the desired accuracy. Several examples illustrate the model applicability to a large range of complex free‐surface flows and demonstrate the effectiveness of the proposed algorithm. Copyright © 2013 John Wiley & Sons, Ltd.
Silicon‐on‐insulator MOSFETs models in analog/RF domain
Authors: Raskin Jean‐Pierre 
Published: November 2013

SUMMARYSeveral physical phenomena specific to silicon‐on‐insulator metal–oxide–semiconductor field‐effect transistors, such as floating body effects, self‐heating, and substrate coupling, are described and modeled. Small‐signal equivalent circuit of ultra‐thin body and thin buried oxide and fin field effect transistor (FinFET) are extracted, and their radio frequency figures of merit as well as their advantages and limitations are presented. We demonstrate the importance of performing wideband characterization at the early stage of the technology development in order to identify the device weaknesses and come up with technological solutions to overcome those. With the ongoing downscaling of the metal–oxide–semiconductor devices, the surrounding of the transistor, that is, the contacts, the access lines, and the substrate, starts to play a major role on the transistor behavior. There is an urgent need to develop adequate models for the new generation of devices valid over a wide frequency band. © (2013) The Authors. INTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS Published by John Wiley & Sons, Ltd.