bluuebunny/crossref_metadata_2025 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

Quorum 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

Ibuprofen 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.
Scale‐up design of a 300 kA magnesium electrolysis cell based on thermo‐electric mathematical models
Authors: Liu Chenglin , Sun Ze , Lu Guimin , Song Xingfu , Ding Yulong , Yu Jianguo
Published: November 2013

Magnesium production process is highly energy intensive. Electrolysis provides an effective route to reduce energy consumption and greenhouse gas emission for the magnesium production. This paper concerns the scale‐up design of a 300 kA magnesium electrolysis cell using a three‐dimensional thermo‐electric mathematical model. The model provides information on the steady‐state thermoelectric fields thus allowing the evaluation of the effects of structure parameters (anode–cathode distance, anode thickness, cathode thickness, anode width, and anode number) on the current intensity, resistance voltage drop, and current density. Non‐dimensional analyses give a linear relation between the current intensity and a set of dimensionless numbers, which upon further comprehensive analyses, gives a criterion for the scale‐up. Such a scale‐up criterion is found to be able to predict, within 1%, the amperage of 300 kA magnesium electrolysis cells. The results suggest that the criterion could be used for the scale‐up design of magnesium electrolysis cells with a high current intensity.
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

During 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.
Semiclassical Limit of Focusing NLS for a Family of Square Barrier Initial Data
Authors: Jenkins Robert , McLaughlin Ken D. T‐R
Published: November 2013

The small dispersion limit of the focusing nonlinear Schrödinger equation (NLS) exhibits a rich structure of sharply separated regions exhibiting disparate rapid oscillations at microscopic scales. The non‐self‐adjoint scattering problem and ill‐posed limiting Whitham equations associated to focusing NLS make rigorous asymptotic results difficult. Previous studies have focused on special classes of analytic initial data for which the limiting elliptic Whitham equations are wellposed. In this paper we consider another exactly solvable family of initial data,the family of square barriers,ψ 0(x) = qχ[−L,L] for real amplitudes q. Using Riemann‐Hilbert techniques, we obtain rigorous pointwise asymptotics for the semiclassical limit of focusing NLS globally in space and up to an O(1) maximal time. In particular, we show that the discontinuities in our initial data regularize by the immediate generation of genus‐one oscillations emitted into the support of the initial data. To the best of our knowledge, this is the first case in which the genus structure of the semiclassical asymptotics for focusing NLS have been calculated for nonanalytic initial data. © 2013 Wiley Periodicals, Inc.
A Multiemitter Localization Comparison of 3D Superresolution Imaging Modalities
Authors: Liu Sheng , Lidke Keith A.
Published: November 2013

Single‐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

Three 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

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

Boreal 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

Benzyltriazoles 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

A 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

A 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

In 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.
Synthesis of foliar and Ca‐S‐Si compound fertilizers from titanium‐bearing blast furnace slag
Authors: Zhang Yue
Published: November 2013

The synthesis of foliar and Ca‐S‐Si compound fertilizers using titanium‐bearing blast furnace slag, potassium bisulfate, citric acid, carbamide, and magnesia as raw materials is reported for the first time. This synthesis enhances the solubility of the slag and transforms the nutritional elements into such forms as to be more readily absorbed by plants. The effects of the process conditions on the dissolution rates of iron, titanium, and magnesium were investigated through the experiment. The results showed that the optimal synthesis process conditions for foliar fertilizer are 560°C for 12 min, with the mass ratio of potassium bisulfate to titanium‐bearing blast furnace slag at 6:1. Under these conditions, more than 85% of the iron, titanium, and magnesium in the slag were converted into water‐soluble species in the foliar fertilizer. Foliar fertilizer with a pH of 6 contained such nutritional elements as nitrogen, sulfur, potassium, iron, titanium, and magnesium, which can all be effectively absorbed by plants. The Ca‐S‐Si compound fertilizer was primarily composed of calcium silicate (soluble in citric acid solution) and calcium sulfate (slightly soluble in water). The application of foliar fertilizer and Ca‐S‐Si fertilizer increased the yield of castor‐oil plants by 35.3% and 21.3%, respectively. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 1316–1321, 2014
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

Structural 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

The 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

Eating 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.
A Variational Bayes Discrete Mixture Test for Rare Variant Association
Authors: Logsdon Benjamin A. , Dai James Y. , Auer Paul L. , Johnsen Jill M. , Ganesh Santhi K. , Smith Nicholas L. , Wilson James G. , Tracy Russell P. , Lange Leslie A. , Jiao Shuo , Rich Stephen S. , Lettre Guillaume , Carlson Christopher S. , Jackson Rebecca D. , O'Donnell Christopher J. , Wurfel Mark M. , Nickerson Deborah A. , Tang Hua , Reiner Alexander P. , Kooperberg Charles ,   on behalf of the NHLBI GO Exome Sequencing Project
Published: November 2013

Recently, many statistical methods have been proposed to test for associations between rare genetic variants and complex traits. Most of these methods test for association by aggregating genetic variations within a predefined region, such as a gene. Although there is evidence that “aggregate” tests are more powerful than the single marker test, these tests generally ignore neutral variants and therefore are unable to identify specific variants driving the association with phenotype. We propose a novel aggregate rare‐variant test that explicitly models a fraction of variants as neutral, tests associations at the gene‐level, and infers the rare‐variants driving the association. Simulations show that in the practical scenario where there are many variants within a given region of the genome with only a fraction causal our approach has greater power compared to other popular tests such as the Sequence Kernel Association Test (SKAT), the Weighted Sum Statistic (WSS), and the collapsing method of Morris and Zeggini (MZ). Our algorithm leverages a fast variational Bayes approximate inference methodology to scale to exome‐wide analyses, a significant computational advantage over exact inference model selection methodologies. To demonstrate the efficacy of our methodology we test for associations between von Willebrand Factor (VWF) levels andVWFmissense rare‐variants imputed from the National Heart, Lung, and Blood Institute's Exome Sequencing project into 2,487 African Americans within theVWFgene. Our method suggests that a relatively small fraction (∼10%) of the imputed rare missense variants withinVWFare strongly associated with lower VWF levels in African Americans.
Calcium phosphate scaffolds mimicking the gradient architecture of native long bones
Authors: Lindner Markus , Bergmann Christian , Telle Rainer , Fischer Horst
Published: November 2013

The 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.
Can Change in FRAX Score Be Used to “Treat to Target”? A Population-Based Cohort Study
Authors: Leslie William D , Majumdar Sumit R , Lix Lisa M , Morin Suzanne N , Johansson Helena , Odén Anders , McCloskey Eugene V , Kanis John A
Published: November 2013

It is unknown how responsive the Fracture Risk Assessment (FRAX) tool is to osteoporosis treatment (OTX) or whether it can serve as a target for “goal-directed” treatment. We studied 11,049 untreated women aged ≥50 years undergoing baseline and follow-up DXA examinations in Manitoba, Canada. We identified clinical risk factors, intervening OTX based on medication possession ratios (MPR), and incident fractures. FRAX scores for major osteoporotic and hip fractures were computed for each scan using the most current (updated) FRAX inputs. Over 4 years, median FRAX scores showed an increase of 1.1% for major fractures and 0.3% for hip fractures, including women highly adherent to OTX (0.6% and 0.1% increases). Few (2.2%) highly adherent women had a decrease in major fracture probability exceeding 4%, whereas 9.0% had a decrease in hip fracture probability exceeding 1%. Compared with untreated women, OTX was associated with a higher dose-dependent likelihood of attenuating the expected increase in major fracture risk: adjusted odds ratios (aOR) 2.3 (95% confidence interval [CI] 1.8–2.9) for MPR <0.50; 7.3 (95% CI 5.6–9.6) for MPR 0.50–0.79; and 12.0 (95% CI 9.5–15.2) for MPR ≥0.80. In the 4 years after the second DXA scan, 620 (6%) women had major fractures (152 hip fractures). FRAX scores were strongly predictive of incident major fractures (adjusted hazard ratios [aHR] per SD increase in FRAX 1.8, 95% CI 1.7–1.9) and hip fractures (aHR per SD 4.5, 95% CI 3.7–5.7); however, change in FRAX score was not independently associated with major fracture (p = 0.8) or hip fracture (p = 0.3). In conclusion, FRAX scores slowly increased over time, and this increase was attenuated but not prevented by treatment. Few women had meaningful reductions in FRAX scores, and change in FRAX score did not independently predict incident fracture, suggesting that FRAX with BMD is not responsive enough to be used as a target for goal-directed treatment. © 2014 American Society for Bone and Mineral Research.
An Efficient Synthesis of Pyrrolo[1,2‐a]quinazoline Derivatives in Ionic Liquid Catalyzed by Iodine
Authors: Lu Lian , Yang Ke , Zhang Mei‐Mei , Wang Xiang‐Shan
Published: November 2013

A mild, green, and facile method for the synthesis of 2,3,3a,4‐tetrahydropyrrolo[1,2‐a]quinazoline‐1,5‐dione derivatives is described in high yields by using ionic liquids as green media. The method involves the reaction of 2‐aminobenzamides with 4‐oxopentanoic acid or 4‐aryl‐4‐oxo‐butanoic acid catalyzed by iodine and has the advantages of mild reaction conditions, high yields, one‐pot, operational simplicity, and environmentally benign.
Automated radiosynthesis of no‐carrier‐added 4‐[18F]fluoroiodobenzene: a versatile building block in 18F radiochemistry
Authors: Way Jenilee Dawn , Wuest Frank
Published: November 2013

4‐[18F]Fluoroiodobenzene ([18F]FIB) is a versatile building block in 18F radiochemistry used in various transition metal‐mediated C–C and C–N cross‐coupling reactions and [18F]fluoroarylation reactions. Various synthesis routes have been described for the preparation of [18F]FIB. However, to date, no automated synthesis of [18F]FIB has been reported to allow access to larger amounts of [18F]FIB in high radiochemical and chemical purity. Herein, we describe an automated synthesis of no‐carrier‐added [18F]FIB on a GE TRACERlab™ FX automated synthesis unit starting from commercially available (4‐iodophenyl)diphenylsulfonium triflate as the labelling precursor. [18F]FIB was prepared in high radiochemical yields of 89 ± 10% (decay‐corrected, n = 7) within 60 min, including HPLC purification. The radiochemical purity exceeded 95%, and specific activity was greater than 40 GBq/µmol. Typically, from an experiment, 6.4 GBq of [18F]FIB could be obtained starting from 10.4 GBq of [18F]fluoride. Copyright © 2013 John Wiley & Sons, Ltd.
Characterization of antagonistic‐potential of two Bacillus strains and their biocontrol activity against Rhizoctonia solani in tomato
Authors: Solanki Manoj Kumar , Singh Rajesh Kumar , Srivastava Supriya , Kumar Sudheer , Kashyap Prem Lal , Srivastava Alok K.
Published: November 2013

To investigate the biocontrol mechanism of two antagonistic Bacillus strains (Bacillus subtilis MB14 and Bacillus amyloliquefaciens MB101), three in vitro antagonism assays were screened and the results were concluded that both strains inhibited Rhizoctonia solani growth in a similar manner by dual culture assay, but the maximum percent of inhibition only resulted with MB101 by volatile and diffusible metabolite assays. Moreover, cell free supernatant (CFS) of MB101 also showed significant (p > 0.05) growth inhibition as compared to MB14, when 10 and 20% CFS mix with the growth medium of R. solani. After in vitro‐validation, both strains were evaluated under greenhouse and the results concluded that strain MB101 had significant biocontrol potential as compared to MB14. Strain MB101 was enhanced the plant height, biomass and chlorophyll content of tomato plant through a higher degree of root colonization. In field trials, strain MB101 showed higher lessening in root rot symptoms with significant fruit yield as compare to strain MB14 and infected control. Next to the field study, the presence of four antibiotic genes (srfAA, fenD, ituC, and bmyB) also concluded the antifungal nature of both Bacillus strains. Phylogenetic analysis of protein sequences revealed a close relatedness of three genes (srfAA, fenD, and ituC) with earlier reported sequences of B. subtilis and B. amyloliquefaciens. However, bmyB showed heterogeneity in among both strains (MB14 and MB101) and it may be concluded that higher degree of antagonism, root colonization and different antibiotic producing genes may play an important role in biocontrol mechanism of strain MB101.
Design of negative metamaterial cell with nematic liquid crystal operating in M band
Authors: Tarnowski Karol , Salejda Włodzimierz
Published: November 2013

A design of a tunable metamaterial cell operating at 85 GHz based on split ring resonators and thin wires is presented. A tunability of the transmission characteristic is assured by a nematic liquid crystal layer. Numerical simulations performed with the finite element method for different orientations of liquid crystal molecules allowed to determine the tunablity range for the resonance frequency and the real part of the effective refractive index. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:39–41, 2014
Compact four‐loop‐antenna system for concurrent, 2.4‐ and 5‐GHz WLAN operation
Authors: Su Saou‐Wen
Published: November 2013

A new, small‐sized, multiple‐loop‐antenna system easily constructed from a single metal plate and able to generate concurrent 2.4 and 5 GHz bands for wireless local area network (WLAN) operation is presented. The design comprises four one‐wavelength loop antennas, arranged perpendicular to and set along a square antenna ground, and occupies overall dimensions 10 mm × 75 mm × 75 mm. The four loops and the antenna ground were all integrated into one‐piece flat plate. The loop was bent few times in a compact fashion such that parts of the antenna resonance path were merged into the ground plane. In this case, a multiantenna system with a simple structure and compact size was achieved for the WLAN applications. Good radiation characteristics were also obtained. Details of the design are described in the article. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:208–215, 2014
The design of double ridge waveguide filter using conventional stepped impedance low‐pass filter method
Authors: Yazdani Mohsen , Murphy Luke , Mallahzadeh Alireza , Arvas Ercument , Mautz Joseph
Published: November 2013

A simple design procedure for a double ridge waveguide low‐pass filter (LPF) is proposed in this article. The procedure follows similar steps involved in a stepped impedance microstrip LPF. The starting point is calculating lumped element low‐pass prototypes and converting them to the double ridge waveguide sections. Step discontinuities are also studied and a lumped element model is proposed by comparing S parameters calculated by HFSS software. The results are then applied to design a six order maximally flat double ridge LPF with 4 GHz cutoff frequency. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:120–124, 2014
Modeling and characterization of spiral resonators embedded in suspended microstrip line for application in low‐loss diplexer
Authors: Gorski Przemyslaw , Jaworski G.
Published: November 2013

This article presents the design and realization of anovel, low‐loss, compact diplexer providing high selectivity and verygood separation between very narrow spaced working channels for application in the ESEO satellite transceiver. The diplexer is based on spiral resonators (SR) embedded in the suspended microstrip line and forming band‐stop filter structures. For design purpose, the equivalent‐circuit model of the SR resonator embedded in microstrip line is derived, analyzed, and verified. The influence of the model parameters on S11 and S21 characteristics has been studied and discussed. The double stage filter with embedded SR resonators has been described. A novel method is proposed to precisely control the filter selectivity, bandwidth, and the position of S11 minimum. The filter has been applied in the diplexer design. The measured performance of the manufactured diplexer prototype exhibits good properties and good agreement with the simulation results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:131–135, 2014
Triple‐band compact monopole antenna with modified SS‐CML units loading
Authors: Deng Sheng‐Liang , Li Rui , Xie Jiao‐Jiao , Yin Ying‐Zeng
Published: November 2013

Triple‐band compact monopole antenna with SS‐CML units loading is proposed in this article. On the basis of mathematical analysis to equal electrical length SS‐CML unit, extended analysis to the unequal case is done. The design method is presented by CRLH‐TL theory. The multifrequency performance of the antenna by changing the current phase through the monopole is achieved. Simulated results show that the antenna can operate at three separate frequency bands of 1.36–1.69 GHz 2.17–2.59 GHz, and 3.38–3.83 GHz, with return loss less than −10 dB. Measurements and EM simulations are in good agreement with the theoretical analysis. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:152–158, 2014
Swept‐frequency order‐recursive method of moments for the efficient analysis of resonant microwave circuits
Authors: Naishadham Krishna
Published: November 2013

In the analysis of resonant microwave circuits by the method of moments (MoM), we typically subdivide the surface in terms of cell density determined by the smallest wavelength and compute the response at several frequencies using this single mesh. Although interpolation can be used in frequency, this approach typically involves matrix operations of complexity O (kN3) at the k discrete frequencies of MoM computation, and can become prohibitive for large structures. In this article, we develop an order‐recursive method for solving the linear system, wherein the solution at the higher frequencies is iteratively constructed from the LU decomposition at the lower frequencies without having to solve the linear system from scratch at each frequency. The proposed order‐recursive MoM allows for systematic adaptive gridding with the increase in frequency, and results in a large portion of matrix recomputation to be avoided, potentially enabling significant reduction in computation time and memory. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:195–198, 2014
Reduction of cross polar radiation of a dual trace omnidirectional microstrip antenna array by using dumbbell‐shaped resonator
Authors: Ghosh Chandan Kumar , Parui Susanta Kumar
Published: November 2013

A compact dual trace omnidirectional microstrip antenna array (DTOMAA) has been designed for WLAN application. The array is then integrated with dumbbell‐shaped resonator (DSR) for reducing cross‐polar (XP) radiation. The antenna is composed of five rectangular‐shaped patch elements arranged alternately on the top and bottom surfaces of the substrate. The antenna exhibits a gain of 12.0 dBi, band width (BW) of 250 GHz, and return loss (RL) of −26 dB. By the introduction of DSR, the XP level is reduced by 7.0 dB without affecting other characteristics like copolar radiation, resonance frequency, and BW of the array. Simulated results show that the proposed antenna offers good impedance matching, high gain, and bandwidth. The simulation results are in good agreement with the measured values. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:141–145, 2014
Wideband circularly polarized conformal strip fed three layer hemispherical dielectric resonator antenna with parasitic patch
Authors: Kakade Anandrao B. , Kumbhar M. S.
Published: November 2013

In this work, a circularly polarized conformal strip fed three‐layer hemispherical dielectric resonator antenna (HDRA) with parasitic patch is analyzed theoretically and experimentally. The effect of position of conformal strip and parasitic patch at first and third dielectric layer interfaces of three‐layer HDRA is investigated for impedance and axial ratio (AR) bandwidths. The optimized permittivities of the layers and conformal strip and patch locations are found for three‐layer HDRA to realize wide impedance and AR bandwidths. The antenna structure is analyzed using Green's function and method of moments approach. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:72–77, 2014
Design equations for dual wideband matching of capacitive coupling element antennas
Authors: Lehtovuori Anu , Valkonen Risto , Ryynänen Jussi , Valtonen Martti
Published: November 2013

To promote efficient design of dual‐band antennas, this article proposes a diplexer‐type matching topology and presents simple formulae to design dual‐band matching networks for capacitive coupling element antennas having strongly frequency‐dependent impedances. Various realistic examples show that wide passbands in cellular communication frequencies can be achieved with only four matching elements. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:236–240, 2014
A compact 4 × 4 butler matrix on double‐layer substrate
Authors: Ausordin Siti Fatimah , Abdul Rahim Sharul Kamal , Seman Norhudah , Dewan Raimi , Sa'ad BashirMuhammad
Published: November 2013

A novel 4 × 4 Butler matrix (BM) on double‐layer substrate is presented. The design of the multilayered BM configuration successfully removes the need for a crossover component by utilizing a double‐layer substrate structure. With the elimination of the crossover, space consumption by the microwave circuit of the BM is reduced significantly. The BM is developed by means of four proposed 3‐dB compact couplers using dual transmission lines on a double‐layer substrate and two 45° phase shifters. The proposed BM components are designed using CST Microwave Studio 2010 and fabricated using inexpensive FR‐4 substrate to operate at 2.45 GHz. The simulated and measured performances in terms of S‐parameters and phase differences for each 3 dB coupler, 45° phase shifter, and BM are presented. Good agreement in beam direction results between the MATLAB (matrix laboratory) simulator and measurement is accomplished with a deviation of ±8°. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:223–229, 2014
Very compact multiband chip antenna for GNSS‐WiFi‐WiMax applications
Authors: Ren Yu‐Jiun , Warden James
Published: November 2013

A very compact multiband internal antenna for handsets and tablets is presented. The proposed antenna is targeted to cover popular noncellular applications including GNSS, WiFi (IEEE 802.11a/b/g), and WiMax (Bands 3A/4/5). This work examines a new ceramic material suitable for the internal antenna design which gives a shorter guided wavelength and multiple resonances to achieve antenna size reduction, sufficient space utilization, and bandwidth increase. The occupied volume of the antenna radiator is only 12 × 4 × 3 mm3, approximately equal to 0.06λm × 0.02λm × 0.016λm (λm is the longest wavelength of the applications) so the antenna can be placed in the device flexibly. The proposed antenna should be the smallest antenna covering GNSS‐WiFi‐WiMax ever reported. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:169–175, 2014
An M‐shaped monopole‐like slot UWB antenna
Authors: Shrivastava Manoj K. , Gautam A. K. , Kanaujia Binod K.
Published: November 2013

An M‐shaped monopole‐like slot Ultra wideband (UWB) antenna is proposed for UWB applications. The proposed antenna usages, an M‐shaped radiator in place of the conventional monopole patch antenna to achieve UWB frequency. The ground plane is also modified by cutting rectangular slots. Therefore, the ground plane works like a radiator that resonates at lower band of UWB. The antenna is practically fabricated and simulated. Measured results show a good agreement with simulated results. The prototype with compact overall size of 36 mm × 36 mm × 1.6 mm achieves good impedance matching, constant gain, and stable radiation patterns over an operating bandwidth of 2.38–12.40 GHz (10.02 GHz). © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:127–131, 2014
In line 40 Gb/s group‐velocity dispersion monitoring
Authors: Sousa A. , Andre P.
Published: November 2013

In this article, we propose a technique to monitor the group‐velocity dispersion (GVD) of an optical signal modulated at 40 Gb/s. The described method is based on the measurement of the electrical signal power at the clock frequency and is able to return the magnitude value and sign of the GVD. We show that this technique is capable to return the GVD in the range [−60, 60] ps/nm, with an error of 3 ps/nm. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:206–208, 2014