bluuebunny/crossref_metadata_2025 huggingface dataset:
Biological Treatment Offers Lower‐Cost Nitrate Removal Option
Authors: Mackey Erin , Cleveland Chris , Carlo Penny , Zacheis Adam , Brown Jess
Published: September 2012

Using microbial biomass to treat groundwater provides new opportunities for U.S. utilities to address widespread nitrate contamination, eliminate traditional waste streams, achieve greater water recovery, and save money.
Concrete Pipe: Installation Strategies Ensure Longevity and Performance
Authors: Deremiah Rick
Published: September 2012

This is the first of two articles on best practices for concrete pressure pipe. This article details installation strategies that will help ensure longevity and optimal performance. Next month's article will explore long‐term maintenance and assessment strategies.
Bleach Safety—Build a Supplier—Customer Partnership
Authors: Fast Shane
Published: September 2012

When used properly, bleach, or sodium hypochlorite, offers tremendous benefits, including water treatment, household disinfection, and even medical care. The general rule of thumb is to never mix sodium hypochlorite with any other chemical, unless adequate engineering controls and personal protective equipment are in place.
Symmetric Large‐Area Metal‐Molecular Monolayer‐Metal Junctions by Wedging Transfer
Authors: Krabbenborg Sven O. , Wilbers Janine G. E. , Huskens Jurriaan , van der Wiel Wilfred G.
Published: September 2012

A method is described for fabricating and electrically characterizing large‐area (100–400 μm2) metal‐molecular monolayer‐metal junctions with a relatively high overall yield of ≈45%. The measurement geometry consists of ultra‐smooth (template‐stripped) patterned Au bottom electrodes, combined with ultra‐smooth top Au electrodes deposited using wedging transfer. The fabrication method is applied to the electrical characterization of Au‐alkanethiol self‐assembled monolayer‐Au junctions. An exponential decay of the current density is found for increasing the chain length of the alkanethiols, in agreement with earlier studies. The symmetric device geometry, and flexibility for contacting monolayers with various end groups are important advantages compared to existing techniques for electrically characterizing molecular monolayers.
Skutterudite Unicouple Characterization for Energy Harvesting Applications
Authors: Muto Andrew , Yang Jian , Poudel Bed , Ren Zhifeng , Chen Gang
Published: September 2012

Skutterudites are promising thermoelectric materials because of their high figure of merit, ZT, and good thermomechanical properties. This work reports the effective figure of merit, ZTeff, and the efficiency of skutterudite legs and a unicouple working under a large temperature difference. The p‐ and n‐type legs are fabricated with electrodes sintered directly to the skutterudite during a hot pressing process. CoSi2 is used as the electrode for the n‐type skutterudite (Yb0.35Co4Sb12) and Co2Si for the p‐type skutterudite (NdFe3.5Co0.5Sb12). A technique is developed to measure the ZTeff of individual legs and the efficiency of a unicouple. An ZTeff of 0.74 is determined for the n‐type legs operating between 52 and 595 °C, and an ZTeff of 0.51 for the p‐type legs operating between 77 and 600 °C. The efficiency of the p–n unicouple is determined to be 9.1% operating between ∼70 and 550 °C.
A Study on the Correlation Between Structure and Hole Transport in Semi‐Crystalline Regioregular P3HT
Authors: Shen Xiaobo , Duzhko Volodimyr V. , Russell Thomas P.
Published: September 2012

A correlation between the hole transport and corresponding structural properties of the bulk regioregular poly(3‐hexylthiophene) (rr‐P3HT) is studied as a function of temperature by the time‐of‐flight (TOF) and wide angle X‐ray diffraction (WAXD) techniques. The thermally‐reversible structural evolution along the (100) and (020) directions in a semi‐crystalline rr‐P3HT can be divided into two distinct temperature regions. At T > 120 °C, a large thermal expansion along the π–π stacking direction in the nanocrystals and a deteriorated ordering in the material result in negative slopes of temperature and electric field dependences of hole mobility. The WAXD data suggest that the hole transport is limited by a decrease in the crystallinity and by an increase in the hopping distance along the π‐π stacking direction, while the Gaussian Disorder Model (GDM) with temperature‐independent parameters cannot be applied. At T < 120 °C, the transport‐related structural changes are negligible and the temperature and electric field dependences of hole mobility can be described by the GDM with constant energetic (σ ∼ 120 meV) and positional disorder parameters (Σ ∼ 3.33). These values suggest that the hole transport is limited by the amorphous phase, as commonly seen in disordered polymers. Moreover, a regiorandom P3HT (rra‐P3HT), which shows a temperature‐independent intermolecular distance of ∼15.3Å, provides a route for separate examination of the amorphous phase in rr‐P3HT.
Dark matter and cosmic structure
Authors: Frenk C.S. , White S.D.M.
Published: September 2012

The current standard model for the evolution of cosmic structure is reviewed, tracing its development over the last forty years and focussing specifically on the role played by numerical simulations and on aspects related to the nature of dark matter.
Cyclic carbonate synthesis from epoxides and CO2 over cyanocobalamin/n‐Bu4NI
Authors: Bai Dongsheng , Jing Huanwang , Wang Guangjian
Published: September 2012

The synthesis of cyclic carbonates from epoxides and carbon dioxide catalyzed by cyanocobalamin and n‐Bu4NI system was achieved under 0.8 MPa CO2 pressure at 140°C without organic solvents. Propylene carbonate was obtained in 99% yield within 6 h under the optimized reaction conditions. The cyanocobalamin catalyst could be recycled with water and retained moderate catalytic activity. Copyright © 2012 John Wiley & Sons, Ltd.
Low‐dimensional modeling of linear heat transfer systems using incremental the proper orthogonal decomposition method
Authors: Xu Chao , Schuster Eugenio
Published: September 2012

In this work, we propose the incremental proper orthogonal decomposition (POD) method and the recursive Galerkin projection to achieve model order reduction (MOR) for high‐dimensional dynamical systems arising in the processes of heat transfer for green buildings. For MOR of high‐dimensional dynamical systems, we use a batch of historic data to initially extract a sequence of POD modes and derive a low‐dimensional system to approximate the high‐dimensional heat transfer system. Then, we check the prediction error at every subsequent sampling moment by using the obtained POD modes. If the approximation error is larger than the pre‐given threshold value, we then add the new snapshot into the collected sampling ensemble. Instead of recalculating the POD‐oriented eigenvalue decomposition problem at each ensemble augmentation (which is time‐consuming), the incremental POD method applies the updated singular value decomposition approach to increase the number of POD modes and adjust the shape of POD modes, and also change corresponding POD eigenvalues through a matrix rotation transformation. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.
Reaction‐Based Colorimetric and Ratiometric Fluorescence Sensor for Detection of Cyanide in Aqueous Media
Authors: Lin Yan‐Duo , Pen Yung‐Shu , Su Weiting , Liau Kang‐Ling , Wen Yun‐Sheng , Tu Chin‐Hsin , Sun Chia‐Hsing , Chow Tahsin J.
Published: September 2012

A stilbene‐based compound (1) has been prepared and was highly selective for the detection of cyanide anion in aqueous media even in the presence of other anions, such as F−, Cl−, Br−, I−, ClO4−, H2PO4−, HSO4−, NO3−, and CH3CO2−. A noticeable change in the color of the solution, along with a prominent fluorescence enhancement, was observed upon the addition of cyanide. The color change was observed upon the nucleophilic addition of the cyanide anion to the electron‐deficient cyanoacrylate group of 1. The spectral changes induced by the reaction were analyzed by comparison with two model compounds, such as compound 2 with dimethyl substituents and compound 3 without a cyanoacrylate group. An intramolecular charge‐transfer (ICT) mechanism played a key role in the sensing properties, and the mechanism was supported by DFT/TDDFT calculations.
Probing the Selectivity of Azomethine Imine Cycloaddition to Single‐Walled Carbon Nanotubes by Resonance Raman Spectroscopy
Authors: Bayazit Mustafa K. , Coleman Karl S.
Published: September 2012

Selective covalent surface modification of single‐walled carbon nanotubes (SWNTs) is of great importance to various carbon nanotube‐based applications as it might offer an alternative method for enriching metallic and semiconducting nanotubes. Herein, we report on the surface modification of SWNTs through 1,3‐dipolar cycloaddition of 3‐phenyl‐phthalazinium‐1‐olate, which is a stable and reactive azomethine imine. For this reaction, microwave heating was found to be more efficient than conventional and solvent‐free heating. The sensitivity of cycloaddition to the molecular structure of SWNTs was probed using resonance Raman spectroscopy with three different laser excitations. Based on the obtained results, azomethine imine addition to the surface of nanotubes is selective for metallic and large‐diameter semiconducting SWNTs. Thermogravimetric analysis coupled with mass spectrometry showed that fragments released at high temperatures corresponded to the phenylphthalazine group, thus confirming the covalent surface functionalization. Modified SWNTs were further characterized by X‐ray photoelectron and UV/Vis‐NIR spectroscopies.
Actuator Fault Reconstruction for Systems with Monotone Nonlinearities
Authors: Liu Hongyuan , Duan Zhisheng
Published: September 2012

This paper considers observer‐based fault reconstruction for systems with monotone nonlinearities. The nonlinear term in the observer error dynamics satisfies a sector property. Using Lyapunov redesign techniques, a continuous nonlinear error feedback is designed according to the slope property of the nonlinear term to stabilize the error dynamics. Hence, the convergence of observer error is independent of the Lipschitz constant. If the observer error converges to zero asymptotically, then the continuous error feedback can be used to reconstruct the faults. As an extension, an adaptive scheme is developed for systems where the arguments of nonlinear functions are perturbed by unknown parameters. Finally, simulations of an electric driving system are presented to show the effectiveness of the schemes.
Expression and mutation analyses implicate ARHGAP29 as the etiologic gene for the cleft lip with or without cleft palate locus identified by genome‐wide association on chromosome 1p22
Authors: Leslie Elizabeth J. , Mansilla M. Adela , Biggs Leah C. , Schuette Kristi , Bullard Steve , Cooper Margaret , Dunnwald Martine , Lidral Andrew C. , Marazita Mary L. , Beaty Terri H. , Murray Jeffrey C.
Published: September 2012

BACKGROUND

Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is a common birth defect with complex etiology reflecting the action of multiple genetic and environmental factors. Genome‐wide association studies have successfully identified five novel loci associated with NSCL/P, including a locus on 1p22.1 near the ABCA4 gene. Because neither expression analysis nor mutation screening support a role for ABCA4 in NSCL/P, we investigated the adjacent gene ARHGAP29.

METHODS

Mutation screening for ARHGAP29 protein coding exons was conducted in 180 individuals with NSCL/P and controls from the United States and the Philippines. Nine exons with variants in ARHGAP29 were then screened in an independent set of 872 cases and 802 controls. Arhgap29 expression was evaluated using in situ hybridization in murine embryos.

RESULTS

Sequencing of ARHGAP29 revealed eight potentially deleterious variants in cases including a frameshift and a nonsense variant. Arhgap29 showed craniofacial expression and was reduced in a mouse deficient for Irf6, a gene previously shown to have a critical role in craniofacial development.

CONCLUSION

The combination of genome‐wide association, rare coding sequence variants, craniofacial specific expression, and interactions with IRF6 support a role for ARHGAP29 in NSCL/P and as the etiologic gene at the 1p22 genome‐wide association study locus for NSCL/P. This work suggests a novel pathway in which the IRF6 gene regulatory network interacts with the Rho pathway via ARHGAP29. Birth Defects Research (Part A) 2012. © 2012 Wiley Periodicals, Inc.
New genes expressed in human brains: Implications for annotating evolving genomes
Authors: Zhang Yong E. , Landback Patrick , Vibranovski Maria , Long Manyuan
Published: September 2012

New genes have frequently formed and spread to fixation in a wide variety of organisms, constituting abundant sets of lineage‐specific genes. It was recently reported that an excess of primate‐specific and human‐specific genes were upregulated in the brains of fetuses and infants, and especially in the prefrontal cortex, which is involved in cognition. These findings reveal the prevalent addition of new genetic components to the transcriptome of the human brain. More generally, these findings suggest that genomes are continually evolving in both sequence and content, eroding the conservation endowed by common ancestry. Despite increasing recognition of the importance of new genes, we highlight here that these genes are still seriously under‐characterized in functional studies and that new gene annotation is inconsistent in current practice. We propose an integrative approach to annotate new genes, taking advantage of functional and evolutionary genomic methods. We finally discuss how the refinement of new gene annotation will be important for the detection of evolutionary forces governing new gene origination.
Eu2+ luminescence in SrCaP2O7 pyrophosphate phosphor
Authors: Kohale R.L. , Dhoble S.J.
Published: September 2012

A series of Eu2+ activated SrCaP2O7 pyrophosphate phosphors were synthesized by the modified solid‐state reaction method. The X‐ray diffraction (XRD) and photoluminescence (PL) properties of these phosphors were investigated at room temperature. The excitation spectra indicate that these phosphors can be effectively excited by Hg‐free excitation. The emission spectra exhibit strong blue performance, which is due to the 4f65d1→4f7 transition of Eu2+. The Fourier transform infrared spectrum at room temperature was investigated and surface morphology has been studied by scanning electron microscope. The prepared phosphor exhibited intense blue emission at the 427 nm owing to Eu2+ ion by Hg‐free excitation at 330 nm, that is, solid‐state lighting excitation. Hence, the availability of such a phosphor will significantly help in the growth of blue‐emitting solid‐state lighting applications. Copyright © 2012 John Wiley & Sons, Ltd.
Heterobinuclear Zn‐Ln (Ln = La, Nd, Eu, Gd, Tb, Er and Yb) complexes based on asymmetric Schiff‐base ligand: synthesis, characterization and photophysical properties
Authors: Zhao Shunsheng , Liu Xiangrong , Lü Xingqiang , Wong Wai‐Kwok
Published: September 2012

With a novel asymmetric Schiff‐base zinc complex ZnL (H2L = N‐(3‐methoxysalicylidene)‐N′‐(5‐bromo‐3‐methoxysalicylidene)phenylene‐1,2‐diamine), obtained from phenylene‐1,2‐diamine, 3‐methoxysalicylaldehyde and 5‐bromo‐3‐methoxysalicylaldehyde, as the precursor, a series of heterobinuclear Zn‐Ln complexes [ZnLnL(NO3)3(CH3CN)] (Ln = La, 1; Ln = Nd, 2; Ln = Eu, 3; Ln = Gd, 4; Ln = Tb, 5; Ln = Er, 6; Ln = Yb, 7) were synthesized by the further reaction with Ln(NO3)3·6H2O, and characterized by Fourier transform‐infrared, fast atom bombardment mass spectroscopy and elemental analysis. Photophysical studies of these complexes show that the strong and characteristic near‐infrared luminescence of Nd3+, Yb3+and Er3+ with emissive lifetimes in the microsecond range has been sensitized from the excited state of the asymmetric Schiff‐base ligand due to effective intramolecular energy transfer; the other complexes do not show characteristic emission due to the energy gap between the chromophore and lanthanide ions. Copyright © 2012 John Wiley & Sons, Ltd.
Multiple β‐sheet molecular dynamics of amyloid formation from two ABl‐SH3 domain peptides
Authors: Lapidus Dmitrijs , Duka Vita , Stonkus Vladislavs , Czaplewski Cezary , Liwo Adam , Ventura Salvador , Liepina Inta
Published: September 2012

Molecular dynamics simulations in explicit water were carried out for two stacks, each composed of six 10‐strand antiparallel β‐sheets for two peptides corresponding to the diverging turn of two homologous Abl‐SH3 domains. The first system, referred to as 10×6×MK contained the DLSFMKGE sequence from the Drosophila, while the second one, referred to as 10×6×KK, contained the human DLSFKKGE sequence. It was found that the 10×6×MK β‐sheet stack is stable, but the 10×6×KK β‐sheet stack is not. The stability of the 10×6×MK β‐sheet stack results from the hydrophobic interactions of the methionine and phenylalanine residues and the leucine residues of the neighboring sheets. The Met, Phe, and Leu hydrophobic units make a hydrophobic core for the stack of β‐sheets. During the MD run, the Met, Phe, and Leu residues of the neighboring β‐sheets acted as a conformational switch moving the β‐sheets so that the Phe residue interacted with the Met residue from the neighboring β‐sheet. Replacement of Met by Lys destroys the hydrophobic core, which is the stability factor of the β‐sheet stack. For the 10×6×KK system, individual β‐sheets were preserved during simulations, but the interactions between the β‐sheets were lost. The calculations of a six β‐sheet stack confirm the conclusion drawn from our earlier studies of single β‐sheet systems that the β‐sheets must form stacks to be stabilized. These results suggest that the two conserved basic residues at the diverging turn of SH3 domains could act as gatekeepers to avoid aggregation. © 2012 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 98: 557–566, 2012.
Effects of motivation on reward and attentional networks: an fMRI study
Authors: Ivanov Iliyan , Liu Xun , Clerkin Suzanne , Schulz Kurt , Friston Karl , Newcorn Jeffrey H. , Fan Jin
Published: September 2012

Existing evidence suggests that reward and attentional networks function in concert and that activation in one system influences the other in a reciprocal fashion; however, the nature of these influences remains poorly understood. We therefore developed a three‐component task to assess the interaction effects of reward anticipation and conflict resolution on the behavioral performance and the activation of brain reward and attentional systems. Sixteen healthy adult volunteers aged 21–45 years were scanned with functional magnetic resonance imaging (fMRI) while performing the task. A two‐way repeated measures analysis of variance (ANOVA) with cue (reward vs. non‐reward) and target (congruent vs. incongruent) as within‐subjects factors was used to test for main and interaction effects. Neural responses to anticipation, conflict, and reward outcomes were tested. Behaviorally there were main effects of both reward cue and target congruency on reaction time. Neuroimaging results showed that reward anticipation and expected reward outcomes activated components of the attentional networks, including the inferior parietal and occipital cortices, whereas surprising non‐rewards activated the frontoinsular cortex bilaterally and deactivated the ventral striatum. In turn, conflict activated a broad network associated with cognitive control and motor functions. Interaction effects showed decreased activity in the thalamus, anterior cingulated gyrus, and middle frontal gyrus bilaterally when difficult conflict trials (e.g., incongruent targets) were preceded by reward cues; in contrast, the ventral striatum and orbitofrontal cortex showed greater activation during congruent targets preceded by reward cues. These results suggest that reward anticipation is associated with lower activation in attentional networks, possibly due to increased processing efficiency, whereas more difficult, conflict trials are associated with lower activity in regions of the reward system, possibly because such trials are experienced as less rewarding.
Motivations and Barriers to Corporate Environmental Management
Authors: Ervin David , Wu JunJie , Khanna Madhu , Jones Cody , Wirkkala Teresa
Published: September 2012

This paper integrates two conceptual frameworks, utility maximization and institutional theory, to analyze voluntary corporate environmental management. The utility maximization or economic approach centers on motivations to decrease cost, increase revenue and improve manager utility. Institutional theory emphasizes how external pressures from market and non‐market constituents shape the firm's environmental efforts. We view the two frameworks as complementary and postulate a model that includes both types of influences. Survey data from six major industries consisting of a diverse set of facilities are used to estimate the effects of economic and institutional factors on a facility's use of environmental practices and pollution‐prevention activities. Our results support the hypothesized model, and show that cost barriers, management attitudes toward environmental stewardship, company ownership and external institutional forces, including competitiveness, investor and regulatory pressures, all affect a facility's environmental practices and pollution prevention activities. Findings suggest that a multifaceted policy strategy is needed to advance corporate environmental management across diverse firms. Copyright © 2012 John Wiley & Sons, Ltd and ERP Environment
The Inactivation Mechanism of Human Group IIA Phospholipase A2 by Scalaradial
Authors: Margarucci Luigi , Monti Maria Chiara , Chini Maria Giovanna , Tosco Alessandra , Riccio Raffaele , Bifulco Giuseppe , Casapullo Agostino
Published: September 2012

Secretory phospholipases A2 (sPLA2s) are implicated in the pathogenesis of several inflammation diseases, such as rheumatoid arthritis, septic shock, psoriasis, and asthma. Thus, an understanding of their inactivation mechanisms could be useful for the development of new classes of chemical selective inhibitors. In the marine environment, several bioactive terpenoids possess interesting anti‐inflammatory activity, often through covalent and/or noncovalent inactivation of sPLA2. Herein, we report the molecular mechanism of human group IIA phospholipase A2 (sPLA2‐IIA) inactivation by Scalaradial (SLD), a marine 1,4‐dialdehyde terpenoid isolated from the sponge Cacospongia mollior and endowed with a significant anti‐inflammatory profile. Our results have been collected by a combination of biochemical approaches, advanced mass spectrometry, surface plasmon resonance, and molecular modeling. These suggest that SLD acts as a competitive inhibitor. Indeed, the sPLA2‐IIA inactivation process seems to be driven by the noncovalent recognition process of SLD in the enzyme active site and by chelation of the catalytic calcium ion. In contrast, covalent modification of the enzyme by the SLD dialdehyde moiety emerges as only a minor side event in the ligand–enzyme interaction. These results could be helpful for the rational design of new PLA2 inhibitors that would be able to selectively target the enzyme active site.
Mixing Analysis for a Fermentation Broth of the Fungus Beauveria bassiana under Different Hydrodynamic Conditions in a Bioreactor
Authors: Núñez‐Ramírez D. M. , Valencia‐López J. J. , Calderas F. , Solís‐Soto A. , López‐Miranda J. , Medrano‐Roldán H. , Medina‐Torres L.
Published: September 2012

The performances of radial‐axial flow (Rushton‐Maxflo impellers) and axial‐radial flow (Maxflo‐Rushton impellers) mixers in the laminar‐transitional flow regime were experimentally and numerically investigated with Newtonian and non‐Newtonian fluids. The rheological properties for a fermentation broth consisting of the fungus Beauveria bassiana were studied under different hydrodynamic conditions in these systems. The bioreactor was a continuous stirred‐tank reactor (CSTR), set at different stirring velocities. The rheology of the systems exhibited shear‐thinning behavior which was modeled with the power law model. The experimental hydrodynamics and configuration modes were compared and simulated with a model fluid system and by numerical criteria (computational fluid dynamics). The R‐M mode was found to be more efficient than the M‐R rotating mode in terms of energy and homogenization time. The results will help in the optimization of scale‐up production of these fungi.
A real‐time Mooney‐viscosity prediction model of the mixed rubber based on the Independent Component Regression‐Gaussian Process algorithm
Authors: Song Kai , Wu Fang , Tong Tuo‐peng , Wang Xiao‐jing
Published: September 2012

With the rapid development of rubber industry, it becomes more and more important to improve the performance of the quality control system of rubber mixing process. Unfortunately, the large measurement time delay of Mooney viscosity, one of the most important quality parameters of mixed rubber, badly blocks the further development of the issue. The independent component regression‐Gaussian process (ICR‐GP) algorithm is used to solve such typical nonlinear “black‐box” regression problem for the first time to predict Mooney viscosity. In the ICR‐GP method, the non‐Gaussian information is extracted by the independent component regression method firstly, and then the residual Gaussian information is extracted by the Gaussian process method. Meanwhile, both the linear and nonlinear relationships between the input and output variables can be extracted through the ICR‐GP method. With the fact that there is no need to optimize parameters, the ICR‐GP method is especially suitable for “black‐box” regression problems. The highest prediction accuracy was achieved at M = 0.8765 (the root mean square error), which was high enough considering the measuring accuracy (M = ±0.5) of the Mooney viscometer. It is by using the online‐measured rheological parameters as the input variables that the measurement time delay of Mooney viscosity could be dramatically decreased from about 240 to 2 min. Consequently, such Mooney‐viscosity prediction model is very helpful for the development of the rubber mixing process, especially of the emerging one‐step rubber mixing technique. The practical applications performed on the rubber mixing process in a large‐scale tire factory strongly proved the outstanding regression performance of this ICR‐GP Mooney‐viscosity prediction model. Copyright © 2012 John Wiley & Sons, Ltd.
Poly(9,9′‐diheylfluorene carbazole) Functionalized with Reduced Graphene Oxide: Convenient Synthesis using Nitrogen‐Based Nucleophiles and Potential Applications in Optical Limiting
Authors: Xu Xiujuan , Chen Jun , Luo Xiaoliang , Lu Jingjing , Zhou Haixin , Wu Wenbo , Zhan Hongbing , Dong Yongqiang , Yan Shouke , Qin Jingui , Li Zhen
Published: September 2012

Covalently functionalized reduced graphene oxide (RGO) sheet was prepared by treating nitrogen‐centered anions generated from poly(9,9′‐diheylfluorene carbazole) (PCF) with GO. The resultant hybrids with different chemical behavior were separated by centrifugation. The covalent modification was fully characterized by IR spectroscopy, UV/Vis spectroscopy, thermogravimetric analysis (TGA), Raman spectroscopy, TEM, and SEM. It was found that RGO‐PCF‐s, the soluble part, was split into small platelets with a size of about 200 nm, and the hydrophobic polymer PCF became hydrophilic after wrapping by RGO. The content of RGO in RGO‐PCF‐s was about 11.9 %, and the hybrid material showed good dispersion stability in water. Besides, RGO‐PCF‐i, the insoluble part, with larger size, displayed excellent optical‐limiting response, in which both nonlinear absorption and nonlinear scattering play important roles. As nitrogen‐centered anions are an important type of intermediates in chemistry, this one‐step “grafting‐to” strategy could be used to obtain RGO‐based materials with different applications.
A Native‐Chemical‐Ligation‐Mechanism‐Based Ratiometric Fluorescent Probe for Aminothiols
Authors: Yuan Lin , Lin Weiying , Xie Yinan , Zhu Sasa , Zhao Sheng
Published: September 2012

Thiol‐containing amino acids (aminothiols) such as cysteine (Cys) and homocysteine (Hcy) play a key role in various biological processes including maintaining the homeostasis of biological thiols. However, abnormal levels of aminothiols are associated with a variety of diseases. The native chemical ligation (NCL) reaction has attracted great attention in the fields of chemistry and biology. NCL of peptide segments involves cascade reactions between a peptide‐α‐thioester and an N‐terminal cysteine peptide. In this work, we employed the NCL reaction mechanism to formulate a Förster resonance energy transfer (FRET) strategy for the design of ratiometric fluorescent probes that were selective toward aminothiols. On the basis of this new strategy, the ratiometric fluorescent probe 1 for aminothiols was judiciously designed. The new probe is highly selective toward aminothiols over other thiols and exhibits a very large variation (up to 160‐fold) in its fluorescence ratio (I458/I603). The new fluorescent probe is capable of ratiometric detection of aminothiols in newborn calf and human serum samples and is also suitable for ratiometric fluorescent imaging of aminothiols in living cells.
Photophysical Analysis of 1,10‐Phenanthroline‐Embedded Porphyrin Analogues and Their Magnesium(II) Complexes
Authors: Ishida Masatoshi , Lim Jong Min , Lee Byung Sun , Tani Fumito , Sessler Jonathan L. , Kim Dongho , Naruta Yoshinori
Published: September 2012

The synthesis, characterization, photophysical properties, and theoretical analysis of a series of tetraaza porphyrin analogues (HPn: n=1–4) containing a dipyrrin subunit and an embedded 1,10‐phenanthroline subunit are described. The meso‐phenyl‐substituted derivative (HP1) interacts with a Mg2+ salt (e.g., MgCl2, MgBr2, MgI2, Mg(ClO4)2, and Mg(OAc)2) in MeCN solution, thereby giving rise to a cation‐dependent red‐shift in both the absorbance‐ and emission maxima. In this system, as well as in the other HPn porphyrin analogues used in this study, the four nitrogen atoms of the ligand interact with the bound magnesium cation to form Mg2+–dipyrrin–phenanthroline complexes of the general structure MgXPn (X=counteranion). Both single‐crystal X‐ray diffraction analysis of the corresponding zinc‐chloride derivative (ZnClP1) and fluorescence spectroscopy of the Mg‐adducts that are formed from various metal salts provide support for the conclusion that, in complexes such as MgClP1, a distorted square‐pyramidal geometry persists about the metal cation wherein a chloride anion acts as an axial counteranion. Several analogues (HPn) that contain electron‐donating and/or electron‐withdrawing dipyrrin moieties were prepared in an effort to understand the structure–property relationships and the photophysical attributes of these Mg–dipyrrin complexes. Analysis of various MgXPn (X=anion) systems revealed significant substitution effects on their chemical, electrochemical, and photophysical properties, as well as on the Mg2+‐cation affinities. The fluorescence properties of MgClPn reflected the effect of donor‐excited photoinduced electron transfer (d‐PET) processes from the dipyrrin subunit (as a donor site) to the 1,10‐phenanthroline acceptor subunit. The proposed d‐PET process was analyzed by electron paramagnetic resonance (EPR) spectroscopy and by femtosecond transient absorption (TA) spectroscopy, as well as by theoretical DFT calculations. Taken together, these studies provide support for the suggestion that a radical species is produced as the result of an intramolecular charge‐transfer process, following photoexcitation. These photophysical effects, combined with a mixed dipyrrin–phenanthroline structure that is capable of effective Mg2+‐cation complexation, lead us to suggest that porphyrin‐inspired systems, such as HPn, have a role to play as magnesium‐cation sensors.
Understanding the Solvent Effect on the Catalytic Oxidation of 1,4‐Butanediol in Methanol over Au/TiO2 Catalyst: NMR Diffusion and Relaxation Studies
Authors: D'Agostino Carmine , Brett Gemma L. , Miedziak Peter J. , Knight David W. , Hutchings Graham J. , Gladden Lynn F. , Mantle Mick D.
Published: September 2012

The effect of water on the catalytic oxidation of 1,4‐butanediol in methanol over Au/TiO2 has been investigated by catalytic reaction studies and NMR diffusion and relaxation studies. The addition of water to the dry catalytic system led to a decrease of both conversion and selectivity towards dimethyl succinate. Pulsed‐field gradient (PFG)‐NMR spectroscopy was used to assess the effect of water addition on the effective self‐diffusivity of the reactant within the catalyst. NMR relaxation studies were also carried out to probe the strength of surface interaction of the reactant in the absence and presence of water. PFG‐NMR studies revealed that the addition of water to the initial system, although increasing the dilution of the system, leads to a significant decrease of effective diffusion rate of the reactant within the catalyst. From T1 and T2 relaxation measurements it was possible to infer the strength of surface interaction of the reactant with the catalyst surface. The addition of water was found to inhibit the adsorption of the reactant over the catalyst surface, with the T1/T2 ratio of 1,4‐butanediol decreasing significantly when water was added. The results overall suggest that both the decrease of diffusion rate and adsorption strength of the reactant within the catalyst, due to water addition, limits the access of reactant molecules to the catalytic sites, which results in a decrease of reaction rate and conversion.
Andhraxylocarpins A–E: Structurally Intriguing Limonoids from the True Mangroves Xylocarpus granatum and Xylocarpus moluccensis
Authors: Li Jun , Li Min‐Yi , Bruhn Torsten , Götz Daniel C. G. , Xiao Qiang , Satyanandamurty Tirumani , Wu Jun , Bringmann Gerhard
Published: September 2012

Five new limonoids, including andhraxylocarpins A and B (1 and 2) which contain a 9‐oxa‐tricyclo[3.3.2.17, 10]undecane‐2‐ene motif, andhraxylocarpins C and D (3 and 4), which contain a (Z)‐bicyclo[5.2.1]dec‐3‐en‐8‐one substructure, and andhraxylocarpin E (5), which contains a tricyclo[3.3.1.13, 6]decane‐9‐one scaffold, were isolated from the seeds of two true mangroves, Xylocarpus granatum and Xylocarpus moluccensis, that were collected in the estuaries of Andhra Pradesh, India. The absolute configurations of these compounds were determined by extensive NMR investigations, single‐crystal X‐ray diffraction analysis, and by circular dichroism and optical rotatory dispersion spectroscopy, in combination with quantum‐chemical calculations. The pronounced structural diversity of limonoids from these mangroves might originate from environmental factors.
Analysis of the Electronic Circular Dichroism Spectrum of (−)–[9](2,5)Pyridinophane
Authors: Padula Daniele , Di Bari Lorenzo , Santoro Fabrizio , Gerlach Hans , Rizzo Antonio
Published: September 2012

The results of a combined experimental and theoretical study of the electronic circular dichroism spectrum of (−)–[9] (2,5)Pyridinophane are presented. The features observed in the measured spectrum in the 180–350 nm wavelength region are reproduced by a series of calculations carried out within a density functional time‐dependent approach, coupled with a vibronic analysis allowing rationalizing unambiguously the chiral response of the molecule. Chirality 24:994–1004, 2012. © 2012 Wiley Periodicals, Inc.
Efficient Calculation of ROA Tensors with Analytical Gradients and Fragmentation
Authors: Thorvaldsen Andreas J. , Gao Bin , Ruud Kenneth , Fedorovsky Maxim , Zuber Gérard , Hug Werner
Published: September 2012

We present the results of calculations of Raman optical activity spectra of sizable systems from optical tensors of the fragments, the tensors calculated by an analytic approach at the time‐dependent Hartree–Fock level of theory. The analytic approach permits large basis sets which, together with the limited geometrical extent of the fragments, obviates the need for the use of London‐type orbitals. The implementation of the analytical gradient approach is formulated in the atomic orbital basis by using the elements of the density matrix as variational parameters. This makes the approach directly applicable to linear scaling methods. We do not solve the response equations for the geometrical distortions of the nuclei but determine instead the second‐order perturbed densities with respect to the electromagnetic field perturbations. The number of perturbed density matrices that needs to be determined is thus independent of the number of nuclei, making the approach applicable to fragments with many nuclei and with good quality basis sets. Compared to numerical differentiation schemes, the analytical approach is about 10 times faster even for moderately sized molecules. Chirality 24:1018–1030, 2012. © 2012 Wiley Periodicals, Inc.
The Fokker‐Planck Equation – A Way to Describe Axial Transport and Mixing Processes in a Tube Reactor
Authors: Sommer Karl , Schlosser Eva , Dauth Heinz
Published: September 2012

Die Fokker‐Planck‐Gleichung wird zur Beschreibung von kontinuierlichen Prozessen verwendet. In dieser Arbeit werden damit die axialen Transportvorgänge in einem Rohrreaktor beschrieben. Hierfür werden unterschiedliche Produkte und unterschiedliche Maschinenparameter verwendet. Somit wird der Einfluss der Drehzahl und der Partikelgröße untersucht. Mit den entstandenen Ergebnissen soll die Korrelation zwischen den Koeffizienten und den Parametern hergestellt werden.
Application of radioactive particle tracking to indicate shed fouling in the stripper section of a fluid coker
Authors: Sanchez Francisco J. , Granovskiy Mikhail
Published: September 2012

The stripper section of a fluid‐coker consists of a system of baffles (sheds) that enhances the removal efficiency of entrained and adsorbed hydrocarbons from the fluidised coke‐particles. If the particles contain a thin liquid film layer of heavy hydrocarbons, making them excessively ‘wet’ or ‘sticky’, and if they stay in contact with sheds for too long, solid deposits are formed that lead to stripper fouling. Extensive fouling decreases stripping efficiency and liquid product yield and can shorten run‐times between shutdowns. Because of the fouling, the shape of sheds mostly changes by increasing their surfaces thickness. An early indication of that fouling and the ability to follow its development are essential for choosing optimal parameters of the process. The radioactive particle tracking (RPT) method has been tested to determine its applicability to indicate the change in the shape of internals within a fluidised bed reactor when direct observation is impossible. A single radioactive tracer‐particle has been traced in experiments lasting from 2 to 6 h. The experiments were conducted in a lab‐scale, cold‐flow fluidised bed into which a single shed with walls of different thickness was incorporated. This experimental fluidised bed provides intensive solid phase mixing that allows a single tracer‐particle to be located in any place within the reactor. By registering the frequency of the tracer‐particle appearance within a defined internal space surrounding the shed, the shape of shed was reconstructed. The conducted experiments suggest that RPT technique allows for tracking internals' fouling within a fluidised bed reactor. © 2012 Canadian Society for Chemical Engineering
Hydrolysis of imidazole and 2‐chloropyridine under subcritical and supercritical water conditions
Authors: Barrera‐Ventura Carmen , Salvatierra Dolors , Giralt Francesc , Giralt Jaume
Published: September 2012

Imidazole and 2‐chloropyridine were used as model molecules to investigate the acid hydrolysis kinetics of agrochemicals in high‐temperature water in a batch reactor system at 28 MPa. Pseudo‐first‐order hydrolysis reaction rate constants for the acid hydrolysis of Imidazole and 2‐chloropyridine were determined in the temperature ranges 200–600 and 400–575°C, respectively, at 28 MPa. Rate constants for both compounds increased with temperature with a local maximum observed at around 400°C due to changes in the physical properties of the solvent. Imidazole and 2‐chloropyridine conversions of 0.95 and 0.99999 were respectively attained at the highest temperature after 30 min of reaction. © 2012 Canadian Society for Chemical Engineering
Experimental study of kerosene–water two‐phase flow in a vertical pipe using hot‐film and dual optical probes
Authors: Hamad F. A. , Khan M. K. , Bruun H. H.
Published: September 2012

The local parameters for kerosene–water upward flow are measured in a vertical pipe of 77.8 mm inner diameter at 4200 mm from the inlet (L/D = 54) using hot‐film and dual optical probes. The effect of superficial water velocity and volumetric quality on radial distribution of two‐phase flow parameters is investigated. The results show the following: (i) the profiles of volume fraction and drop frequency are very similar, and increasing superficial water velocity at low volumetric qualities (<18.6%) change the profile from a convex shape with peak at the pipe centreline to uniform then to concave shape with peak near the wall; (ii) the profiles of drop cut chord change from a parabolic shape with peak at centreline for low superficial water velocities to a flat shape at higher superficial water velocity, and the area‐averaged drop diameter decreases with higher superficial water velocities for all volumetric qualities; (iii) velocity profiles for both phases have shapes similar to single phase flow, flatter at higher values of superficial water velocity and volumetric quality and centreline peaked at low superficial water velocities and volumetric qualities; (iv) the slip velocity decreases with radial distance having a peak at centreline and zero values near the wall; (v) introducing kerosene drops into single phase water flow results in a sharp increase in turbulent intensity, particularly at low water velocity, and the difference between the single phase and two‐phase flow turbulence intensities decreases with higher superficial water velocities and (vi) the results show that interfacial area concentration increased with higher volumetric quality and higher number of bubbles thereby increases the contact area between the two phases. © 2012 Canadian Society for Chemical Engineering
Modification of the AMX membrane surface: Temperature dependence of anion exchange equilibrium
Authors: Guesmi Fatma , Hannachi Chiraz , Hamrouni Béchir
Published: September 2012

In order to improve the selectivity of the AMX membrane, a polyethyleneimine (PEI) layer was adsorbed on its surface. Ion exchange isotherms of (Cl−/NO3−), (Cl−/SO42−) and (NO3−/SO42−), using a modified AMX membrane, were established at different temperatures (from 283 to 313 K), with a constant total concentration of 0.3 mol/L and neutral pH. The results obtained with the modified membrane in this range of temperature show that chloride was the most sorbed and the selectivity order was Cl− > NO3− > SO42−. Selectivity coefficients and thermodynamic equilibrium constants, determined for the three binary systems, increased with increasing temperature. These results were compared with those obtained with the unmodified membrane. It was observed that for the modified membrane, the selectivity towards sulphate ion decreased and the modified membrane became more selective towards monovalent anions. Ion exchange equilibrium at temperatures 283, 298 and 313 K of the studied binary systems were found to be endothermic processes.
Limitations in health care access and utilization among long‐term survivors of adolescent and young adult cancer
Authors: Kirchhoff Anne C. , Lyles Courtney R. , Fluchel Mark , Wright Jennifer , Leisenring Wendy
Published: September 2012

BACKGROUND:

Health care outcomes for long‐term survivors of adolescent and young adult (AYA) cancer were compared with young adults without a cancer history, using the 2009 Behavioral Risk Factor Surveillance System data.

METHODS:

Eligible participants were 20 to 39 years of age. There were N = 979 who self‐reported a cancer diagnosis between the ages of 15 to 34 years and were at least 5 years from diagnosis (excluding nonmelanoma skin cancer). The remaining 67,216 participants with no cancer history were used as controls. Using multivariable regressions, relative risks and 95% confidence intervals were generated to examine the relationship of survivor status on indicators of poor health care (uninsured, no personal health care provider, no routine care, and avoiding seeing a doctor due to cost). Adjusted proportions were calculated by demographic groups. Results are weighted by Behavioral Risk Factor Surveillance System survey design.

RESULTS:

Although the proportion uninsured did not differ (21% of survivors vs 23% of controls), AYA survivors reported forgoing care due to cost at higher levels than controls (relative risk = 1.67, 95% CI = 1.44‐1.94). Cost barriers were particularly high for survivors aged 20 to 29 years (44% vs 16% of controls; P < .001) and female survivors (35% vs 18% of controls; P < .001). Survivors reporting poorer health had more cost barriers. Moreover, uninsured survivors tended to report lower use of health care than did controls.

CONCLUSIONS:

AYA cancer survivors may forgo health care due to cost barriers, potentially inhibiting the early detection of late effects. Expanding health insurance coverage for young cancer survivors may be insufficient without adequate strategies to reduce their medical cost burdens. Cancer 2012. © 2012 American Cancer Society.
Ion Interactions with a New Ditopic Naphthalimide‐Based Receptor: A Photophysical, NMR and Theoretical (DFT) Study
Authors: Mohan Vaisakh , Nijamudheen A. , Das Sudhir Kumar , Sahu Prabhat K. , Kar Usha Pallabi , Rahaman Abdur , Sarkar Moloy
Published: September 2012

A new multi‐component chemosensor system comprising a naphthalimide moiety as fluorophore is designed and developed to investigate receptor–analyte binding interactions in the presence of metal and non‐metal ions. A dimethylamino moiety is utilized as receptor for metal ions and a thiourea receptor, having acidic protons, for binding anions. The system is characterized by conventional analytical methods. The absorption and fluorescence spectra of the system consist of a broad band typical for an intramolecular charge transfer (ICT). The effects of various metal‐ion additives on the spectral behavior of the present sensor system are examined in acetonitrile. It is found that among the metal ions studied, alkali/alkaline earth‐metal ions and transition‐metal ions modulate the absorption and fluorescence spectra of the system. As an additional feature, the anion signaling behavior of the system in acetonitrile is studied. A decrease in fluorescence efficiency of the system is observed upon addition of fluoride and acetate anions. Fluorescence quenching is most effective in the case of fluoride ions. This is attributed to the enhancement of the photoinduced electron transfer from the anion receptor to the fluorophore moiety. Hydrogen‐bond interactions between the acidic NH protons of the thiourea moiety and the F− anions are primarily attributed to the fluoride‐selective signaling behavior. Interestingly, a negative cooperativity for the binding event is observed when the interactions of the system are studied in the presence of both Zn2+ and F− ions. NMR spectroscopy and theoretical calculations are also carried out to better understand the receptor–analyte binding.