bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non‐native N‐Aroyl L‐Homoserine Lactones Are Potent Modulators of the Quorum Sensing Receptor RpaR in Rhodopseudomonas palustris
Authors: McInnis Christine E. , Blackwell Helen E. 
Published: November 2013

AbstractQuorum sensing (QS) is a process by which bacteria use low‐molecular‐weight signaling molecules (or autoinducers) to assess their local population densities and alter gene expression levels at high cell numbers. Many Gram‐negative bacteria use N‐acyl L‐homoserine lactones (AHLs) with aliphatic acyl groups as signaling molecules for QS. However, bacteria that utilize AHLs with aroyl acyl groups have been recently discovered; they include the metabolically versatile soil bacterium Rhodopseudomonas palustris, which uses p‐coumaroyl HL (p‐cAHL) as its QS signal. This autoinducer is especially unusual because its acyl group is believed to originate from a monolignol (i.e., p‐coumarate) produced exogenously by plants in the R. palustris environment, rather than through the endogenous fatty acid biosynthesis pathway like other native AHLs. As such, p‐cAHL could signal not only bacterial density, but also the availability of an exogenous plant‐derived substrate and might even constitute an interkingdom signal. Like other Gram‐negative bacteria, QS in R. palustris is controlled by the p‐cAHL signal binding its cognate LuxR‐type receptor, RpaR. We sought to determine if non‐native aroyl HLs (ArHLs) could potentially activate or inhibit RpaR in R. palustris, and thereby modulate QS in this bacterium. Herein, we report the testing of a set of synthetic ArHLs for RpaR agonism and antagonism by using a R. palustris reporter strain. Several potent non‐native RpaR agonists and antagonists were identified. Additionally, the screening data revealed that lower concentrations of ArHL are required to strongly agonize RpaR than to antagonize it. Structure–activity relationship analyses of the active ArHLs indicated that potent RpaR agonists tend to have sterically small substituents on their aryl groups, most notably in the ortho position. In turn, the most potent RpaR antagonists were based on either the phenylpropionyl HL (PPHL) or the phenoxyacetyl HL (POHL) scaffold, and many contained an electron‐withdrawing group at either the meta or para positions of the aryl ring. To our knowledge, the compounds reported herein represent the first abiotic chemical modulators of RpaR, and more generally, the first abiotic ligands capable of intercepting QS in bacteria that utilize native ArHL signals. In view of the origins of the p‐cAHL signal in R. palustris, the largely unknown role of QS in this bacterium, and R. palustris' unique environmental lifestyles, we anticipate that these compounds could be valuable as chemical probes to study QS in R. palustris in a range of fundamental and applied contexts.
Distinct Enantiomeric Signals of Ibuprofen and Naproxen in Treated Wastewater and Sewer Overflow
Authors: Khan Stuart J. , Wang Lili , Hashim Nor H. , Mcdonald James A. 
Published: November 2013

ABSTRACTIbuprofen and naproxen are commonly used members of a class of pharmaceuticals known as 2‐arylpropionic acids (2‐APAs). Both are chiral chemicals and can exist as either of two (R)‐ and (S)‐enantiomers. Enantioselective analyses of effluents from municipal wastewater treatment plants (WWTPs) and from untreated sewage overflow reveal distinctly different enantiomeric fractions for both pharmaceuticals. The (S)‐enantiomers of both were dominant in untreated sewage overflow, but the relative proportions of the (R)‐enantiomers were shown to be increased in WWTP effluents. (R)‐naproxen was below method detection limits (<1 ng.L‐1) in sewage overflow, but measurable at higher concentrations in WWTP effluents. Accordingly, enantiomeric fractions (EF) for naproxen were consistently 1.0 in sewage overflow, but ranged from 0.7–0.9 in WWTP effluents. Ibuprofen EF ranged from 0.6–0.8 in sewage overflow and receiving waters, and was 0.5 in two WWTP effluents. Strong evidence is provided to indicate that chiral inversion of (S)‐2‐APAs to produce (R)‐2‐APAs may occur during wastewater treatment processes. It is concluded that this characterization of the enantiomeric fractions for ibuprofen and naproxen in particular effluents could facilitate the distinction of treated and untreated sources of pharmaceutical contamination in surface waters. Chirality 26:739–746, 2013. © 2013 Wiley Periodicals, Inc.
Nuclear factor one B regulates neural stem cell differentiation and axonal projection of corticofugal neurons
Authors: Betancourt Jennifer , Katzman Sol , Chen Bin 
Published: November 2013

ABSTRACTDuring development of the cerebral cortex, neural stem cells divide to expand the progenitor pool and generate basal progenitors, outer radial glia, and cortical neurons. As these newly born neurons differentiate, they must properly migrate toward their final destination in the cortical plate, project axons to appropriate targets, and develop dendrites. However, a complete understanding of the precise genetic mechanisms regulating these steps is lacking. Here we show that a member of the nuclear factor one (NFI) family of transcription factors, NFIB, is essential for many of these processes in mice. We performed a detailed analysis of NFIB expression during cortical development, and investigated defects in cortical neurogenesis, neuronal migration, and differentiation in NfiB−/− brains. We found that NFIB is strongly expressed in radial glia and corticofugal neurons throughout cortical development. However, in NfiB−/− cortices, radial glia failed to generate outer radial glia, subsequently resulting in a loss of late basal progenitors. In addition, corticofugal neurons showed a severe loss of axonal projections, whereas late‐born cortical neurons displayed defects in migration and ectopically expressed the early‐born neuronal marker CTIP2. Furthermore, gene expression analysis, by RNA sequencing, revealed a misexpression of genes that regulate the cell cycle, neuronal differentiation and migration in NfiB−/− brains. Together these results demonstrate the critical functions of NFIB in regulating cortical development. J. Comp. Neurol. 522:6–35, 2014. © 2013 Wiley Periodicals, Inc.
A Multiemitter Localization Comparison of 3D Superresolution Imaging Modalities
Authors: Liu Sheng , Lidke Keith A. 
Published: November 2013

AbstractSingle‐molecule localization‐based superresolution imaging is complicated by emission from multiple emitters overlapping at the detector. The potential for overlapping emitters is even greater for 3D imaging than for 2D imaging due to the large effective “volume” of the 3D point spread function. Overlapping emission can be accounted for in the estimation model, recovering the ability to localize the emitters, but with the caveat that the localization precision has a dependence on the amount of overlap from other emitters. Whether a particular 3D imaging modality has a significant advantage in facilitating the position estimation of overlapping emitters is investigated. The variants of two commonly used and easily implemented imaging modalities for 3D single‐molecule imaging are compared: astigmatic imaging; dual focal plane imaging; and the combination of the two approaches, dual focal plane imaging with astigmatism. The Cramér–Rao lower bound is used to quantify the multiemitter estimation performance by calculating the theoretical best localization precision under a multiemitter estimation model. The performance of these 3D modalities is investigated under a wide range of conditions including various distributions of collected photons per emitter, background counts, pixel sizes, and camera readout noise values. Differences between modalities are small and it is therefore concluded that multiemitter fitting performance should not be a primary factor in selecting between these modalities.
Influence of Chromophore Length and Acceptor Groups on the Optical Properties of Rigidified Merocyanine Dyes
Authors: Kreß Katharina Christina , Fischer Thomas , Stumpe Joachim , Frey Wolfgang , Raith Melanie , Beiraghi Omid , Eichhorn S. Holger , Tussetschläger Stefan , Laschat Sabine 
Published: November 2013

AbstractThree series of rigidified tri‐, penta‐ and heptamethine merocyanine dyes were synthesised. A piperidyl moiety was chosen as the electron‐donating substituent while the electron‐accepting group was varied from ketones to malononitriles and cyanoacetates. The structures of the compounds in the solid state and in solution were elucidated by X‐ray diffraction and NMR spectroscopy, respectively, while optical properties were investigated by absorption and emission spectroscopy. As a general trend, the acceptor properties decrease in the series malononitrile>cyanoacetate>ketone based on the analysis of their solvatochromic behaviour. The experimental results were further supported by calculations at the B3LYP 6‐311+G(d) level of theory.
Nimesulide/Methyl β‐Cyclodextrin Inclusion Complexes: Physicochemical Characterization, Solubility, Dissolution, and Biological Studies
Authors: Auda Sayed H. 
Published: November 2013

Abstract

Preclinical Research

Nimesulide (NIM) is an insoluble nonsteroidal anti‐inflammatory drug (NSAID). Complexation of drug with methyl β‐cyclodextrin was evaluated to improve solubility and dissolution rate of NIM. Complexation was achieved via a coevaporation technique to obtain different drug to polymer molar ratios (1:1, 1:2, and 1:3). The physicochemical characterization of the systems using powder X‐ray diffraction and infrared spectroscopy was carried out to understand the influence of this technological process on the physical status of single components and complex systems and to detect possible interactions between drug and carrier. Moreover, quantitative solubility and in vitro dissolution studies of NIM alone and NIM inclusion complexes were studied in the dissolution media of phosphate buffer pH 5.5 and 7.4. The analysis provided existence of a molecular interaction between drug and carrier together in the complex state. The study showed that the inclusion systems enhanced of drug solubility, dissolution rate, and anti‐inflammatory activity.
Long‐term fertilization of a boreal Norway spruce forest increases the temperature sensitivity of soil organic carbon mineralization
Authors: Coucheney Elsa , Strömgren Monika , Lerch Thomas Z. , Herrmann Anke M. 
Published: November 2013

AbstractBoreal ecosystems store one‐third of global soil organic carbon (SOC) and are particularly sensitive to climate warming and higher nutrient inputs. Thus, a better description of how forest managements such as nutrient fertilization impact soil carbon (C) and its temperature sensitivity is needed to better predict feedbacks between C cycling and climate. The temperature sensitivity of in situ soil C respiration was investigated in a boreal forest, which has received long‐term nutrient fertilization (22 years), and compared with the temperature sensitivity of C mineralization measured in the laboratory. We found that the fertilization treatment increased both the response of soil in situ CO2 effluxes to a warming treatment and the temperature sensitivity of C mineralization measured in the laboratory (Q10). These results suggested that soil C may be more sensitive to an increase in temperature in long‐term fertilized in comparison with nutrient poor boreal ecosystems. Furthermore, the fertilization treatment modified the SOC content and the microbial community composition, but we found no direct relationship between either SOC or microbial changes and the temperature sensitivity of C mineralization. However, the relation between the soil C:N ratio and the fungal/bacterial ratio was changed in the combined warmed and fertilized treatment compared with the other treatments, which suggest that strong interaction mechanisms may occur between nutrient input and warming in boreal soils. Further research is needed to unravel into more details in how far soil organic matter and microbial community composition changes are responsible for the change in the temperature sensitivity of soil C under increasing mineral N inputs. Such research would help to take into account the effect of fertilization managements on soil C storage in C cycling numerical models.
Synthesis of α‐Keto‐1,2,3‐triazoles Through Copper Iodide Catalyzed Oxygenation
Authors: Nawratil Swantje , Grypioti Maria , Menendez Christophe , Mallet‐Ladeira Sonia , Lherbet Christian , Baltas Michel 
Published: November 2013

AbstractBenzyltriazoles have been catalytically oxidized by using CuI and tert‐butyl hydroperoxide to yield phenyl(1H‐1,2,3‐triazol‐4‐yl)methanone derivatives in good yields at room temperature.
Multifunctional Mediating System Composed of a Conducting Polymer Matrix, Redox Mediator and Functionalized Carbon Nanotubes: Integration with an Enzyme for Effective Bioelectrocatalytic Oxidation of Glucose
Authors: Gierwatowska Marta , Kowalewska Barbara , Cox James A. , Kulesza Pawel J. 
Published: November 2013

AbstractA multifunctional mediating system for bioelectrocatalytic oxidation of glucose is described. It comprises a conducting polymer, poly(3,4‐ethylenodioxythiophene), carbon nanotubes modified with 4‐(pyrrole‐1‐yl) benzoic acid that provide carboxyl groups that aid immobilization of glucose oxidase in a conductive three‐dimensional network, tetrathiafulvalene that mediates electron exchange with the enzyme. This composite produces a system that is capable of effective oxidation of glucose to gluconic acid at pH 7. The current is concentration dependent to at least 60 mM and maintains 77 % of initial response for 35 days. Data supporting the utility of this system for electrochemical sensing and biofuel cell technology are presented.
A Future German Energy System with a Dominating Contribution from Renewable Energies: A Holistic Model Based on Hourly Simulation
Authors: Palzer Andreas , Henning Hans‐Martin 
Published: November 2013

AbstractA clear consensus exists in German society that it is necessary to achieve ambitious greenhouse‐gas emission reduction targets and that renewable energies have to play a dominant role in the future German energy‐supply system. However, many questions are still under discussion, for instance about the relevance of the different technologies such as photovoltaic systems or wind energy converters installed offshore in the North Sea and the Baltic Sea. Concerns are often expressed regarding the cost of a future energy system mainly based on renewable energies. To be able to address the raised issues on a scientifically sound basis we have set up a new simulation model REMod‐D (Renewable Energy Model–Deutschland) that models a possible future German energy system for all sectors, including all renewable energy converters, storage components, secondary energy converters, and loads for an entire year based upon an hourly simulation. Moreover, the model includes retrofitting of buildings for energy efficiency as a measure to reduce the future heat loads of the building sector. A generic optimizer is applied to identify system compositions with minimal overall annual cost. After a short introduction about the modeling approach, the results of parameter studies are presented.
Studying Catalyst Activity in an Isomerization Plant to Upgrade the Octane Number of Gasoline by Using a Hybrid Artificial‐Neural‐Network Model
Authors: Sadighi Sepehr , Zahedi Sorood , Hayati Reza , Bayat Mahmood 
Published: November 2013

AbstractIn this study, a hybrid model is presented for estimating the activity of a commercial Pt/zeolite catalyst in an industrial‐scale light naphtha isomerization unit. This model is also capable of predicting the research octane number (RON) and Reid vapor pressure (RVP) of gasoline, the flow rate of product, and the temperature profile of the reactor. In the proposed model, the decay function of heterogeneous catalysts is combined with a recurrent‐layer artificial neural network. To identify the activity of catalyst, a set of 52 data points during 272 days were gathered from the target isomerization plant. From these data, 31 points were selected for training (60 %), 11 data points for testing (20 %) and the remained ones for validating the developed hybrid network (20 %). Results show that the presented hybrid model can acceptably estimate the activity of the catalyst during its life in consideration of all process variables. Moreover, it is confirmed that for unseen (validating) data, the proposed model is capable of predicting RON, RVP, flow rate of gasoline, and the temperatures of the middle and end sections of the isomerization reactor with an average absolute deviations (AAD %) of 0.0769 %, 0.118 %, 0.6945 %, 0.042 %, and 0.1137 %, respectively.
Development and validation of nonlinear computational models of dispersed structures under strong earthquake excitation
Authors: Derkevorkian Armen , Masri Sami F. , Fujino Yozo , Siringoringo Dionysius M. 
Published: November 2013

SUMMARYStructural health monitoring of large multispan flexible bridges is particularly important because of their important role in civil infrastructure and transportation systems. In this study, the response of the Yokohama Bay Bridge (YBB), a three‐span cable‐stayed bridge, to the 2011 Great East Japan Earthquake is used to perform multi‐input multi‐output system identification studies. The extensive multicomponent measurements are also used to develop and validate data‐driven nonlinear mathematical models that can predict the response of YBB to various earthquake records and can accurately estimate its damping characteristics when the system is driven into the nonlinear response range. A combination of least‐square (parametric) and neural network (nonparametric) approaches is used to develop the mathematical models, along with time‐marching techniques for dynamic response calculations. It is shown that the nonlinear mathematical models perform better than the equivalent linear models, both for response prediction and damping estimation. The importance of having an accurate approach for quantifying the damping due to the variety of nonlinear features in the YBB response is shown. This study demonstrates the significance of constructing robust mathematical models that can capture the correct physics of the underlying system and that can be used for computational purposes to augment experimental studies. Given the lack of suitable data sets for full‐scale structures under extreme loads, the availability of the long‐duration measurements from the 2011 Great East Japan Earthquake and its many strong aftershocks provides an excellent opportunity to perform the analyses presented in this study. Copyright © 2013 John Wiley & Sons, Ltd.
Enhancing resilience of highway bridges through seismic retrofit
Authors: Venkittaraman Ashok , Banerjee Swagata 
Published: November 2013

SUMMARYThe present study evaluates seismic resilience of highway bridges that are important components of highway transportation systems. To mitigate losses incurred from bridge damage during seismic events, bridge retrofit strategies are selected such that the retrofit not only enhances bridge seismic performance but also improves resilience of the system consisting of these bridges. To obtain results specific to a bridge, a reinforced concrete bridge in the Los Angeles region is analyzed. This bridge was severely damaged during the Northridge earthquake because of shear failure of one bridge pier. Seismic vulnerability model of the bridge is developed through finite element analysis under a suite of time histories that represent regional seismic hazard. Obtained bridge vulnerability model is combined with appropriate loss and recovery models to calculate seismic resilience of the bridge. Impact of retrofit on seismic resilience is observed by applying suitable retrofit strategy to the bridge assuming its undamaged condition prior to the Northridge event. Difference in resilience observed before and after bridge retrofit signified the effectiveness of seismic retrofit. The applied retrofit technique is also found to be cost‐effective through a cost‐benefit analysis. First order second moment reliability analysis is performed, and a tornado diagram is developed to identify major uncertain input parameters to which seismic resilience is most sensitive. Statistical analysis of resilience obtained through random sampling of major uncertain input parameters revealed that the uncertain nature of seismic resilience can be characterized with a normal distribution, the standard deviation of which represents the uncertainty in seismic resilience. Copyright © 2013 John Wiley & Sons, Ltd.
Prevalence of Eating Disorders amongst Dancers: A Systemic Review and Meta‐Analysis
Authors: Arcelus Jon , Witcomb Gemma L. , Mitchell Alex 
Published: November 2013

AbstractEating disorders in dancers are thought to be common, but the exact rates remain to be clarified. The aim of this study is to systematically compile and analyse the rates of eating disorders in dancers. A literature search, appraisal and meta‐analysis were conducted. Thirty‐three relevant studies were published between 1966 and 2013 with sufficient data for extraction. Primary data were extracted as raw numbers or confidence intervals. Risk ratios and 95% confidence intervals were calculated for controlled studies. The overall prevalence of eating disorders was 12.0% (16.4% for ballet dancers), 2.0% (4% for ballet dancers) for anorexia, 4.4% (2% for ballet dancers) for bulimia and 9.5% (14.9% for ballet dancers) for eating disorders not otherwise specified (EDNOS). The dancer group had higher mean scores on the EAT‐26 and the Eating Disorder Inventory subscales. Dancers, in general, had a higher risk of suffering from eating disorders in general, anorexia nervosa and EDNOS, but no higher risk of suffering from bulimia nervosa. The study concluded that as dancers had a three times higher risk of suffering from eating disorders, particularly anorexia nervosa and EDNOS, specifically designed services for this population should be considered. Copyright © 2013 John Wiley & Sons, Ltd and Eating Disorders Association.
Calcium phosphate scaffolds mimicking the gradient architecture of native long bones
Authors: Lindner Markus , Bergmann Christian , Telle Rainer , Fischer Horst 
Published: November 2013

AbstractThe synthesis of beta‐tricalcium phosphate (β‐TCP) scaffolds offering both the macroporous inner structure required for proper in vivo degradation and a non‐macroporous outer structure for the enhancement of mechanical properties continues to be a challenge. The hypothesis of this study was to realize biomimetic β‐TCP scaffolds with a macroporous inner structure and a compact outer structure using a lost wax casting technique. The porosity, macropore size, interconnectivity of the inner porous structure, and diameter of the outer compact structure were adjusted to specific values using a three‐dimensional wax printer to manufacture the wax molds for the casting process. After the slip casting, the wax was pyrolyzed and the specimens were sintered. The resulting graded β‐TCP scaffolds (porous + compact) were characterized and compared with β‐TCP scaffolds with overall apparent macropores (only porous) and samples without macropores (only compact). The porosity and the compressive strength of the only compact, porous + compact, and only porous β‐TCP samples were 31.4 ± 0.4 vol %, 55.6 ± 0.9 vol %, and 66.9 ± 0.4 vol % and 192 ± 7 MPa, 36 ± 2 MPa, and 9 ± 1 MPa, respectively. The macropore size was 500 µm and the micropore size was up to 10 µm, both featuring a completely open porous structure. From these results, we conclude that the lost wax casting technique offers an excellent method for the fabrication of β‐TCP scaffolds with an inner macroporous structure and compact outer structure which mimics the cancellous and cortical structure of natural bone. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 3677–3684, 2014.