bluuebunny/crossref_metadata_2025 huggingface dataset:
Semiconducting Clathrates Meet Gas Hydrates: Xe24[Sn136]
Authors: Karttunen Antti J. , Fässler Thomas F.
Published: April 2014

Semiconducting Group 14 clathrates are inorganic host–guest materials with a close structural relationship to gas hydrates. Here we utilize this inherent structural relationship to derive a new class of porous semiconductor materials: noble gas filled Group 14 clathrates (Ngx[M136], Ng=Ar, Kr, Xe and M=Si, Ge, Sn). We have carried out high‐level quantum chemical studies using periodic Local‐MP2 (LMP2) and dispersion‐corrected density functional methods (DFT‐B3LYP‐D3) to properly describe the dispersive host–guest interactions. The adsorption of noble gas atoms within clathrate‐II framework turned out to be energetically clearly favorable for several host–guest systems. For the energetically most favorable noble gas filled clathrate, Xe24[Sn136], the adsorption energy is −52 kJ mol−1 per guest atom at the LMP2/TZVPP level of theory, corresponding to −9.2 kJ mol−1 per framework Sn atom. Considering that a hypothetical guest‐free Sn clathrate‐II host framework is only 2.6 kJ mol−1 per Sn atom less stable than diamond‐like α‐Sn, the stabilization resulting from the noble gas adsorption is very significant.
Thermal Mass Flow Measurement of Highly Viscous, Non‐Newtonian Polymers
Authors: Schönteich Bernward , Fischer Fabian , Dilger Klaus
Published: April 2014

Die Möglichkeit der auf Konvektion basierenden thermischen Strömungsmessung wird auf ihre Eignung zur Messung von Massenströmen hochviskoser Fluide mit nichtnewtonschen Strömungseigenschaften untersucht. Es wird ein Konzept vorgestellt, wie mit kleinen Sensoren Massenströme gemessen werden können, was neue Möglichkeiten im Bereich der Dosierung und der Strömungsuntersuchung hochviskoser Fluide eröffnet. Die Untersuchungen wurden anhand von Klebstoffen durchgeführt.
Adherence to Dual Antiplatelet Therapy After Coronary Stenting: A Systematic Review
Authors: Czarny Matthew J. , Nathan Ashwin S. , Yeh Robert W. , Mauri Laura
Published: May 2014

Background

Adherence to dual antiplatelet therapy (DAPT) is critical after coronary stenting. Although adherence rates are frequently assessed in clinical trials, adherence rates in the unselected population recommended for treatment but beyond clinical trials are largely unknown. Therefore, we performed a systematic review of published observational studies to describe rates of DAPT adherence, trends in DAPT use over time, and patient‐level factors associated with nonadherence.

Hypothesis

DAPT adherence declines with increasing time after drug‐eluting stent implantation.

Methods

PubMed, Cumulative Index to Nursing and Allied Health Literature, Embase, and Web of Knowledge were searched through November 20, 2012 for studies including patients receiving 1 or more drug‐eluting stents and reporting the use of aspirin and/or thienopyridines, or assessing factors associated with nonadherence to DAPT after bare metal or drug‐eluting stent placement.

Results

We included 34 studies in the description of DAPT adherence and 11 studies in the description of factors associated with nonadherence. Adherence to DAPT and thienopyridines was high at 1 month but declined by 12 months. Aspirin adherence was at least 90% throughout. Factors associated with nonadherence included bleeding, lower education level, immigrant status, and lack of education regarding DAPT.

Conclusions

DAPT adherence is suboptimal at 12 months, and interventions to increase adherence should focus on reducing bleeding risk and improving communication between patients and physicians.
Diversity and wiring variability of visual local neurons in the Drosophila medulla M6 stratum
Authors: Chin An‐Lun , Lin Chih‐Yung , Fu Tsai‐Feng , Dickson Barry J. , Chiang Ann‐Shyn
Published: April 2014

Local neurons in the vertebrate retina are instrumental in transforming visual inputs to extract contrast, motion, and color information and in shaping bipolar‐to‐ganglion cell transmission to the brain. In Drosophila, UV vision is represented by R7 inner photoreceptor neurons that project to the medulla M6 stratum, with relatively little known of this downstream substrate. Here, using R7 terminals as references, we generated a 3D volume model of the M6 stratum, which revealed a retinotopic map for UV representations. Using this volume model as a common 3D framework, we compiled and analyzed the spatial distributions of more than 200 single M6‐specific local neurons (M6‐LNs). Based on the segregation of putative dendrites and axons, these local neurons were classified into two families, directional and nondirectional. Neurotransmitter immunostaining suggested a signal routing model in which some visual information is relayed by directional M6‐LNs from the anterior to the posterior M6 and all visual information is inhibited by a diverse population of nondirectional M6‐LNs covering the entire M6 stratum. Our findings suggest that the Drosophila medulla M6 stratum contains diverse LNs that form repeating functional modules similar to those found in the vertebrate inner plexiform layer. J. Comp. Neurol. 522:3795–3816, 2014. © 2014 Wiley Periodicals, Inc.
Particle‐Size Effects on the Entropy Behavior of a LixFePO4 Electrode
Authors: Kai Kazuhiko , Kobayashi Yo , Miyashiro Hajime , Oyama Gosuke , Nishimura Shin‐ichi , Okubo Masashi , Yamada Atsuo
Published: April 2014

The particle‐size effects on the thermodynamic properties and kinetic behavior of a LixFePO4 electrode have a direct influence on the electrode properties. Thus, the development of high‐performance Li‐ion batteries containing a LixFePO4 cathode requires a complete understanding of the reaction mechanism at the atomic/nano/meso scale. In this work, we report electrochemical calorimetric and potentiometric studies on LixFePO4 electrodes with different particle sizes and clarify the particle‐size effect on the reaction mechanism based on the entropy change of (de)lithiation. Electrochemical calorimetry results show that a reduction in particle size shrinks the miscibility gap of LixFePO4 while potentiometric measurements demonstrate that the LixFePO4 particles equilibrate into either a kinetically metastable state or a thermodynamically stable state depending on the particle size.
Spatially Selective Heteronuclear Multiple‐Quantum Coherence Spectroscopy for Biomolecular NMR Studies
Authors: Sathyamoorthy Bharathwaj , Parish David M. , Montelione Gaetano T. , Xiao Rong , Szyperski Thomas
Published: April 2014

Spatially selective heteronuclear multiple‐quantum coherence (SS HMQC) NMR spectroscopy is developed for solution studies of proteins. Due to “time‐staggered” acquisitioning of free induction decays (FIDs) in different slices, SS HMQC allows one to use long delays for longitudinal nuclear spin relaxation at high repetition rates. To also achieve high intrinsic sensitivity, SS HMQC is implemented by combining a single spatially selective 1H excitation pulse with nonselective 1H 180° pulses. High‐quality spectra were obtained within 66 s for a 7.6 kDa uniformly 13C,15N‐labeled protein, and within 45 and 90 s for, respectively, two proteins with molecular weights of 7.5 and 43 kDa, which were uniformly 2H,13C,15N‐labeled, except for having protonated methyl groups of isoleucine, leucine and valine residues.
Interphase Evolution at Two Promising Electrode Materials for Li‐Ion Batteries: LiFePO4 and LiNi1/2Mn1/2O2
Authors: Dupré Nicolas , Cuisinier Marine , Martin Jean‐Frederic , Guyomard Dominique
Published: April 2014

The present review reports the characterization and control of interfacial processes occurring on olivine LiFePO4 and layered LiNi1/2Mn1/2O2, standing here as model compounds, during storage and electrochemical cycling. The formation and evolution of the interphase created by decomposition of the electrolyte is investigated by using spectroscopic tools such as magic‐angle‐spinning nuclear magnetic resonance (7Li, 19F and 31P) and electron energy loss spectroscopy, in parallel to X‐ray photoelectron spectroscopy, to quantitatively describe the interphase and unravel its architecture. The influence of the pristine surface chemistry of the active material is carefully examined. The importance of the chemical history of the surface of the electrode material before any electrochemical cycling and the strong correlation between interface phenomena, the formation/evolution of an interphase, and the electrochemical behavior appear clearly from the use of these combined characterization probes. This approach allows identifying interface aging and failure mechanisms. Different types of surface modifications are then investigated, such as intrinsic modifications upon aging in air or methods based on the use of additives in the electrolyte or carbon coatings on the surface of the active materials. In each case, the species detected on the surface of the materials during storage and cycling are correlated with the electrochemical performance of the modified positive electrodes.
Highlighting the Effects of Co‐eluting Interferences on Compound‐Specific Stable Isotope Analysis of Polycyclic Aromatic Hydrocarbons by Using Comprehensive Two‐Dimensional Gas Chromatography
Authors: Gauchotte‐Lindsay Caroline , McGregor Laura A. , Assal Antoine , Thomas Russell , Kalin Robert M.
Published: May 2014

Accuracy is the most important issue when performing compound‐specific stable isotope analysis of polycyclic aromatic hydrocarbons (PAHs) extracted from complex samples. It depends on two main factors: the possible isotopic fractionation of the compounds during extraction and the potential co‐elution with interfering compounds with different isotopic signatures. Herein, a simplified pressurised liquid extraction method for compound‐specific stable isotope analysis of PAHs in non‐aqueous‐phase liquids of coal tar is presented. Samples extracted using the new method and by fractionation on a silica gel column were analysed by comprehensive two‐dimensional gas chromatography. It was possible to evaluate the effect of co‐elution on the carbon and hydrogen stable isotope signatures of the 16 US EPA priority PAHs in coal tars with various proportions of aromatic and aliphatic content. Even in samples that presented a good baseline resolution, the PAHs of interest co‐eluted with other aromatic compounds with a notable effect on their stable isotope values; this demonstrated the necessity to check the quality of all extraction and clean‐up methods (either the simplified pressurised liquid extraction or more traditional labour‐intensive methods) for more complex samples prior to data interpretation. Additionally, comprehensive two‐dimensional gas chromatography enabled visualisation of the suspected co‐elution for the first time.
Aerosol‐Assisted Chemical Vapour Deposition of Transparent Zinc Gallate Films
Authors: Knapp Caroline E. , Manzi Joe A. , Kafizas Andreas , Parkin Ivan P. , Carmalt Claire J.
Published: April 2014

Aerosol‐assisted chemical vapour deposition (AACVD) reactions of GaMe3, ZnEt2 and the donor‐functionalised alcohol HOCH2CH2OMe (6 equiv.) in toluene resulted in the deposition of amorphous transparent zinc gallate (ZnGa2O4) films at a range of temperatures (350–550 °C). The zinc–gallium oxide films were analyzed by scanning electron microscopy, X‐ray photoelectron spectroscopy (XPS), energy‐dispersive X‐ray analysis, glancing‐angle X‐ray powder diffraction (XRD) and optical studies. The optimum growth temperature was found to be 450 °C, which produced transparent films with excellent coverage of the substrate. XPS confirmed the presence of zinc, gallium and oxygen in the films. Annealing these films at 1000 °C resulted in crystalline films and glancing‐angle powder XRD showed that a zinc gallate spinel framework with a lattice parameter of a=8.336(5) Å was adopted.
VEGF modulates synaptic activity in the developing spinal cord
Authors: Guérit Sylvaine , Allain Anne‐Emilie , Léon Céline , Cazenave William , Ferrara Napoleone , Branchereau Pascal , Bikfalvi Andréas
Published: April 2014

Although it has been documented that the nervous and the vascular systems share numerous analogies and are closely intermingled during development and pathological processes, interactions between the two systems are still poorly described. In this study, we investigated whether vascular endothelial growth factor (VEGF), which is a key regulator of vascular development, also modulates neuronal developmental processes. We report that VEGF enhances the gamma‐aminobutyric acid (GABA)/glycinergic but not glutamatergic synaptic activity in embryonic spinal motoneurons (MNs), without affecting MNs excitability. In response to VEGF, the frequency of these synaptic events but not their amplitude was increased. Blocking endogenous VEGF led to an opposite effect by decreasing frequency of synaptic events. We found that this effect occurred specifically at early developmental stages (E13.5 and E15.5) and vanished at the prenatal stage E17.5. Furthermore, VEGF was able to increase vesicular inhibitory amino acid transporter density at the MN membrane. Inhibition of single VEGF receptors did not modify electrophysiological parameters indicating receptor combinations or an alternative pathway. Altogether, our findings identify VEGF as a modulator of the neuronal activity during synapse formation and highlight a new ontogenic role for this angiogenic factor in the nervous system. © 2014 Wiley Periodicals, Inc. Develop Neurobiol 74: 1110–1122, 2014
Does your species have memory? Analyzing capture–recapture data with memory models
Authors: Cole Diana J. , Morgan Byron J. T. , McCrea Rachel S. , Pradel Roger , Gimenez Olivier , Choquet Remi
Published: April 2014

We examine memory models for multisite capture–recapture data. This is an important topic, as animals may exhibit behavior that is more complex than simple first‐order Markov movement between sites, when it is necessary to devise and fit appropriate models to data. We consider the Arnason–Schwarz model for multisite capture–recapture data, which incorporates just first‐order Markov movement, and also two alternative models that allow for memory, the Brownie model and the Pradel model. We use simulation to compare two alternative tests which may be undertaken to determine whether models for multisite capture–recapture data need to incorporate memory. Increasing the complexity of models runs the risk of introducing parameters that cannot be estimated, irrespective of how much data are collected, a feature which is known as parameter redundancy. Rouan et al. (JABES, 2009, pp 338–355) suggest a constraint that may be applied to overcome parameter redundancy when it is present in multisite memory models. For this case, we apply symbolic methods to derive a simpler constraint, which allows more parameters to be estimated, and give general results not limited to a particular configuration. We also consider the effect sparse data can have on parameter redundancy and recommend minimum sample sizes. Memory models for multisite capture–recapture data can be highly complex and difficult to fit to data. We emphasize the importance of a structured approach to modeling such data, by considering a priori which parameters can be estimated, which constraints are needed in order for estimation to take place, and how much data need to be collected. We also give guidance on the amount of data needed to use two alternative families of tests for whether models for multisite capture–recapture data need to incorporate memory.
Intermolecular Interactions in Fluorinated Tetraarylporphyrins: An Experimental and Theoretical Study
Authors: Soman Rahul , Sujatha Subramaniam , De Susmita , Rojisha Vallyanga Chalil , Parameswaran Pattiyil , Varghese Babu , Arunkumar Chellaiah
Published: May 2014

Crystallographic studies of the fluorinated tetraarylporphyrin 5,10,15,20‐tetrakis(2′,3′,5′,6′‐tetrafluoro‐N,N‐dimethyl‐4‐anilinyl)porphyrin and its metal complexes [MTF4DMAP; M = 2H·2H2O, 1; NiII·THF, 2; CuII·5H2O, 3; and ZnII·(THF)2, 4; THF = tetrahydrofuran] are reported. To analyse the weak intermolecular interactions, we have used a combination of energy decomposition analysis and Hirshfeld surface analysis, which allowed us to elucidate the nature of various close contacts. The energy decomposition analysis shows that dispersive interactions involving fluorine atoms significantly contribute to the stabilizing intermolecular interactions. Cooperative weak interactions such as C–F···H/C/F, C–H···π and H···H are responsible for the formation and stabilization of the supramolecular self assemblies.
Hierarchical Self‐Assembly of Luminescent EuIII Complexes on Silicon
Authors: Misztal Kasjan , Tudisco Cristina , Sartori Andrea , Malicka Joanna M. , Castelli Riccardo , Condorelli Guglielmo G. , Dalcanale Enrico
Published: April 2014

We have combined the metal‐coordinating features of phenanthroline with the remarkable complexing properties of tetraphosphonate (Tiiii) cavitands towards N‐methylammonium salts with the aim of assembling novel luminescent ternary complexes. The formation of such complexes was first tested in solution: the charged sarcosine derivative 1, bearing a phenanthroline moiety, was complexed by the cavitand Tiiii‐A, followed by coordination of EuIII–tris(β‐diketonate) complex 2. The occurrence of the self‐assembly has been proven by NMR spectroscopy, mass spectrometry and photophysical measurements. The transfer of this binding protocol to the surface showed the complete orthogonality of these interactions, as verified by control experiments on complexation‐inactive surfaces. The formation of the ternary complexes on the silicon surface was monitored by means of X‐ray photoelectron spectroscopy and luminescence spectroscopy. The emission properties of the silicon‐bound Si‐Tiiii‐B·1·2 and the corresponding ternary complex Tiiii‐A·1·2 in solution are similar, which indicates that the transfer of the self‐assembly process onto silicon does not significantly perturb the EuIII coordination environment. The self‐assembly protocol illustrated here can be extended to a wide variety of lanthanide ions and can be implemented for applications in sensing, bioimaging and optoelectronic devices.
Genetic diversity and haplotype structure of 24 Y‐chromosomal STR in Chinese Hui ethnic group and its genetic relationships with other populations
Authors: Zhu Bo‐Feng , Zhang Yu‐Dang , Liu Wen‐Juan , Meng Hao‐Tian , Yuan Guo‐Lian , Lv Zhe , Dong Nan , Li Qiong , Yang Chun‐hua , Zhang Yu‐Hong , Hou Yin‐Ling , Qian Li , Fan Shuan‐Liang , Xu Peng
Published: May 2014

In the present study, 24 Y‐chromosomal short tandem repeat (Y‐STR) loci were analyzed in 115 unrelated Hui male individuals from Haiyuan county or Tongxin county, Ningxia Hui Autonomous Region, China, to evaluate the forensic application of the 24 STR loci and to analyze interpopulation differentiations by making comparisons between the Hui group data and previously published data of other 13 populations. A total of 115 different haplotypes were observed on these 24 Y‐STR loci. The gene diversities ranged from 0.4049 (DYS437) to 0.9729 (DYS385a, b). The overall haplotype diversity was 1 at AGCU 24 Y‐STR loci level, while the values were reduced to 0.999237, 0.996949, and 0.996644 at the Y‐filer 17 loci, 11 Y‐STR loci of extended haplotype and 9 Y‐STR loci of minimal haplotype levels, respectively; whereas, haplotype diversity for additional 7 loci (not included in Y‐filer 17 loci) was 0.995271. The pairwise FST, multidimensional scaling plot and neighbor‐joining tree indicated the Hui group had the closest genetic relationship with Sala in the paternal lineage in the present study. In summary, the results in our study indicated the 24 Y‐STRs had a high level of polymorphism in Hui group and hence could be a powerful tool for forensic application and population genetic study.
Determination of estrogens in environmental water samples using 1,3‐dipentylimidazolium hexafluorophosphate ionic liquid as extraction solvent in dispersive liquid–liquid microextraction
Authors: Socas‐Rodríguez Bárbara , Hernández‐Borges Javier , Asensio‐Ramos María , Herrera‐Herrera Antonio V. , Palenzuela Jose A. , Rodríguez‐Delgado Miguel Ángel
Published: May 2014

In this work, the potential of a symmetric dialkyl‐substituted ionic liquid (IL), 1,3‐dipenthylimidazolium hexafluorophosphate ([PPIm][PF6]), as extraction solvent in dispersive liquid–liquid microextraction (DLLME) has been studied for the analysis of a group of three natural (estriol, 17β‐estradiol, and 17α‐estradiol) and four synthetic (17α‐ethynylestradiol, diethylstibestrol, dienestrol, and hexestrol) estrogenic compounds as well as one mycotoxin with estrogenic activity (zearalenone) in different types of water samples (Milli‐Q, mineral, and wastewater). Separation, determination, and quantification were developed by HPLC‐DAD and a fluorescence detector (FD) connected in series. Factors influencing the IL‐DLLME procedure (sample pH, amount of IL, type and volume of disperser solvent, ionic strength, and assistance of vortex agitation) were investigated and optimized by means of a step‐by‐step approach. Once the optimum extraction conditions were established (10 mL of water at pH 8, 60 mg of [PPIm][PF6], 500 μL of ACN as disperser solvent and vortex agitation for 1 min), the calibration curves of the whole method (IL‐DLLME‐HPLC‐DAD/FD) were obtained and precision and accuracy were evaluated. It was demonstrated that the developed methodology was repeatable, accurate, and selective with limits of detection in the 0.30–0.57 μg/L and 13.8–37.1 μg/L range for FD and DAD, respectively. Relative recovery values were higher than 85% for the different types of water samples and the Student's t test demonstrated that there were not significant differences between the added and the found concentration.
Achieving professional success in US government, academia, and industry: An EMGS commentary
Authors: Poirier Miriam C. , Schwartz Jeffrey L. , Aardema Marilyn J.
Published: May 2014

One of the goals of the EMGS is to help members achieve professional success in the fields they have trained in. Today, there is greater competition for jobs in genetic toxicology, genomics, and basic research than ever before. In addition, job security and the ability to advance in one's career is challenging, regardless of whether one works in a regulatory, academic, or industry environment. At the EMGS Annual Meeting in Monterey, CA (September, 2013), the Women in EMGS Special Interest Group held a workshop to discuss strategies for achieving professional success. Presentations were given by three speakers, each representing a different employment environment: Government (Miriam C. Poirier), Academia (Jeffrey L. Schwartz), and Industry (Marilyn J. Aardema). Although some differences in factors or traits affecting success in the three employment sectors were noted by each of the speakers, common factors considered important for advancement included networking, seeking out mentors, and developing exceptional communication skills. Environ. Mol. Mutagen. 55:525–529, 2014. © 2014 Wiley Periodicals, Inc.
Evidence of biogeomorphic patterning in a low‐relief karst landscape
Authors: Watts Adam C. , Watts Danielle L. , Cohen Matthew J. , Heffernan James B. , McLaughlin Daniel L. , Martin Jonathan B. , Kaplan David A. , Osborne Todd Z. , Kobziar Leda N.
Published: May 2014

Patterned landscapes are often evidence of biotic control on geomorphic processes, emerging in response to coupled ecosystem processes acting at different spatial scales. Self‐reinforcing processes at local scales expand patches, while self‐inhibiting processes, operating at a distance, impose limits to expansion. In Big Cypress National Preserve (BICY) in southwest Florida, isolated forested wetland depressions (cypress domes) appear to be evenly distributed within a mosaic of short‐hydroperiod marshes and pine uplands. To test the hypothesis that the apparent patterning is regular, we characterized frequency distributions and spatial patterns of vegetation communities, surface and bedrock elevation, and soil properties (thickness and phosphorus content). Nearest neighbor distances indicate strongly significant wetland spatial overdispersion, and bedrock elevations exhibited periodic spatial autocorrelation; both observations are consistent with regular patterning. Bedrock elevations and soil P were clearly bimodal, suggesting strong positive feedbacks on wetland patch development. Soil‐surface elevations exhibited weaker bimodality, indicating smoothing of surface morphology by some combination of sediment transport, mineral reprecipitation, and organic matter production. Significant negative autocorrelation of bedrock elevations at scales similar to wetland spacing suggest the presence of distal negative feedbacks on patch expansion. These findings support the inference of regular patterning, and are consistent with the presence of local positive feedbacks among hydroperiod, vegetation productivity and bedrock dissolution. These processes are ultimately constrained by distal negative feedbacks, potentially induced by landscape scale limitations on the water volume required to enable this biogeomorphic mechanism. Copyright © 2014 John Wiley & Sons, Ltd.
Heterogeneous Aging Within PEMFC Stacks
Authors: Chatillon Y. , Bonnet C. , Lapicque F.
Published: May 2014

Evaluation of PEM fuel cell aging occurring in various operating conditions is usually conducted in single cell configuration for which various electrochemical methods can be used. Aging phenomena in stack is often investigated either in a global manner or by basic measurements of variables, e.g. individual cell voltages. This paper presents the results of aging investigation of three‐cell stacks using crossed linked electrochemical methods giving access to the time variations of ohmic and charge transfer resistance of the three cathodes, as well as the electrochemical surface area and the fuel crossover over more than 1,000 h at 0.3 A cm–2 upon air humidification. Consistency between the various methods employed was discussed and demonstrated. In addition to the case of a stack formed by three sane cells, the case of a stack comprising a defective cell – previously aged under oxidative conditions – placed between two sane MEAs was investigated: the pre‐ageing of this cell was shown to slightly accelerate the aging under long‐term operation. Besides, it was observed that in both stacks, the back cell – i.e. located far from the stack inlet and outlet – suffered much more from the long‐term run than the two other cells.
Using the Multiple SEA Method to Synthesize Pt/Carbon Xerogel Electrocatalysts for PEMFC Applications
Authors: Zubiaur A. , Chatenet M. , Maillard F. , Lambert S. D. , Pirard J.‐P. , Job N.
Published: May 2014

Pt/carbon xerogel (CX) catalysts were synthesized by the multiple strong electrostatic adsorption (SEA) method. This method consists of the impregnation of a carbon support (here, a CX) by a solution containing hexachloroplatinic acid (H2PtCl6). The impregnation pH is precisely chosen to maximize the ion/support interactions. The Pt precursor solution can be re‐used so as to avoid Pt waste during the process. Five catalysts with increasing Pt weight percentage were synthesized by multiple impregnation (from one to five times), and were characterized by transmission electron microscopy, X‐ray diffraction, and CO stripping. The specific activity of the Pt particles for the oxygen reduction reaction (ORR) was measured in liquid electrolyte with a rotating disk electrode system. The Pt particles are ca. 2.5 nm in diameter and display electroactive specific surface areas of ca. 95 cm2 gPt–1. The five Pt/CX catalysts present the same specific activity for the ORR: for all the catalysts, the specific activity equals ca. 0.05 mA cm–2Pt at 0.85 V versus NHE and 0.01 mA cm–2Pt at 0.9 V versus NHE.
Evaluating the Effectiveness of Using Flexography Printing for Manufacturing Catalyst‐Coated Membranes for Fuel Cells
Authors: Bois C. , Dumont P. J. J. , Blayo A. , Vincent R. , Nayoze C. , Chaussy D.
Published: May 2014

This study is an evaluation of the effectiveness of the flexography printing process for manufacturing catalyst‐coated membranes (CCMs) for use in proton exchange membrane fuel cells (PEMFCs). Flexography is a maskless and continuous process that is used in large‐scale production with water‐based inks to reduce the cost of production of PEMFC components. Unfortunately, water has undesirable effects on the Nafion® membrane: water wets the membrane surface poorly and causes the membrane to bulge outwards significantly. Membrane printability was improved by pre‐treating membrane samples by water immersion for short periods (<2 min). This pre‐treatment was used to control the membrane deformation before printing to limit the impact of the ink transfer. Water and ink drop deposition experiments were performed to estimate the liquid‐air‐Nafion® apparent contact angle and the locally induced membrane deformation. Despite the short immersion times used in the tests, the immersion pre‐treatment appeared to induce structural modifications that enhanced both the membrane wettability and the dimensional stability. Flexography printability tests were performed on these treated membranes and showed that the dimensional instability of the Nafion® membrane was the critical parameter for limiting the ink transfer. The immersion pre‐treatment improved the printability of the Nafion® membranes, which were used to fabricate cathodes that were tested in an operational fuel cell.
Transoral robotic assisted resection of the parapharyngeal space
Authors: Mendelsohn Abie H.
Published: May 2014

Background

Preliminary case series have reported clinical feasibility and safety of a transoral minimally invasive technique to approach parapharyngeal space masses. With the assistance of the surgical robotic system, tumors within the parapharyngeal space can now be excised safely without neck incisions. A detailed technical description is included.

Methods

After developing compressive symptoms from a parapharyngeal space lipomatous tumor, the patient was referred by his primary otolaryngologist because of poor open surgical access to the nasopharyngeal component of the tumor.

Results

Transoral robotic assisted resection of a 54‐ × 46‐mm parapharyngeal space mass was performed, utilizing 97 minutes of robotic surgical time. Pictorial demonstration of the robotic resection is provided.

Conclusion

Parapharyngeal space tumors have traditionally been approached via transcervical skin incisions, typically including blunt dissection from tactile feedback. The transoral robotic approach offers magnified 3D visualization of the parapharyngeal space that allows for complete and safe resection. © 2014 Wiley Periodicals, Inc. Head Neck 37: 273‐280, 2015
Influence of surgical margins on local recurrence in T1/T2 oral squamous cell carcinoma
Authors: Barry Conor P. , Ahmed Ferhan , Rogers Simon N. , Lowe Derek , Bekiroglu Fazilet , Brown James S. , Shaw Richard J.
Published: May 2014

Background

The purpose of this study was to explore the significance of resection margin status on local recurrence and survival for early (T1/T2) oral cancer and to determine if the significance of the resection margin varies with the biological aggression of the tumor as determined by pN status.

Methods

The influence of resection margin size and local recurrence for 295 patients with pT1/T2 oral cavity squamous cell carcinomas (SCCs) treated by primary surgery, including neck dissection, between 1998 and 2010 was analyzed.

Results

Overall, there was a trend toward increased local recurrence with close or involved margins. When stratified according to nodal status, there was no relationship between margin size and local recurrence for the pN0 group.

Conclusion

The size of the resection margin does not seem to influence local control in stage I/II oral cancer. With future advances in preoperative neck staging, this data may help plan personalized therapy in head and neck cancer. © 2014 Wiley Periodicals, Inc. Head Neck 37: 1176–1180, 2015
Cognitive impairment in temporal lobe epilepsy: Role of online and offline processing of single cell information
Authors: Titiz A. S. , Mahoney J. M. , Testorf M. E. , Holmes G. L. , Scott R. C.
Published: May 2014

Cognitive impairment is a common comorbidity in temporal lobe epilepsy (TLE) and is often considered more detrimental to quality of life than seizures. While it has been previously shown that the encoding of memory during behavior is impaired in the pilocarpine model of TLE in rats, how this information is consolidated during the subsequent sleep period remains unknown. In this study, we first report marked deficits in spatial memory performance and severe cell loss in the CA1 layer of the hippocampus lower spatial coherence of firing in TLE rats. We then present the first evidence that the reactivation of behavior‐driven patterns of activity of CA1 place cells in the hippocampus is intact in TLE rats. Using a template‐matching method, we discovered that real‐time (3–5 s) reactivation structure was intact in TLE rats. Furthermore, we estimated the entropy rate of short time scale (∼250 ms) bursting activity using block entropies and found that significant, extended temporal correlations exist in both TLE and control rats. Fitting a first‐order Markov Chain model to these bursting time series, we found that long sequences derived from behavior were significantly enriched in the Markov model over corresponding models fit on randomized data confirming the presence of replay in shorter time scales. We propose that the persistent consolidation of poor spatial information in both real time and during bursting activity may contribute to memory impairments in TLE rats. © 2014 Wiley Periodicals, Inc.
The effect of maternal body mass index on fetal growth: Use of individualized growth assessment and two‐level linear modeling
Authors: Canavan Timothy P. , Deter Russell L.
Published: May 2014

Purpose

To determine the effect of maternal body mass index on fetal growth using individualized growth assessment and two‐level linear modeling.

Methods

A retrospective review of biometry in the second and third trimesters from 246 normal, term singleton fetuses was performed. Four to eight biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur diaphysis length (FDL) measurements per fetus were available and used to determine second‐trimester growth rates. Expected third‐trimester size trajectories were generated from these data and Percent Deviations [%Dev = ((observed − expected)/expected) × 100] were calculated. Two‐level linear modeling was used to determine %Dev slopes and the effect of body mass index (BMI) on these slopes. Relationships between individual second‐ and third‐trimester slopes and BMI were evaluated using linear regression.

Results

Linear regression analysis of second‐trimester growth indicated no significant relationships between the fetal growth rate and the BMI in the second trimester [R2 (adj): 0.0% to 1.0% except AC in one subgroup (5.6%)]. Regression analysis did not indicate a significant relationship (adj R2: 0%–0.2%) between BMI and third‐trimester %Dev slopes for any anatomic parameter. Two‐level statistical modeling showed no effect of BMI on BPD, AC, or FDL growth and only a moderate effect on the HC growth in the third trimester.

Conclusions

Our findings indicate that the maternal BMI does not have an effect on fetal growth in either the second or the third trimester as determined with individualized growth assessment. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound 42:456–464, 2014
Evidence of distinct populations of hepatitis C virus in the liver and plasma of patients co‐infected with HIV and HCV
Authors: Blackard Jason T. , Ma Gang , Sengupta Satarupa , Martin Christina M. , Powell Eleanor A. , Shata M. Tarek , Sherman Kenneth E.
Published: April 2014

Viral diversity is an important predictor of hepatitis C virus (HCV) treatment response and may influence viral pathogenesis. HIV influences HCV variability in the plasma; however, limited data on viral variability are available from distinct tissue/cell compartments in patients co‐infected with HIV and HCV. Thus, this exploratory study evaluated diversity of the hypervariable region 1 (HVR1) of HCV in the plasma and liver for 14 patients co‐infected with HIV and HCV. Median intra‐patient genetic distances and entropy values were similar in the plasma and liver compartments. Positive immune selection pressure was observed in the plasma for five individuals and in the liver for three individuals. Statistical evidence supporting viral compartmentalization was found in five individuals. Linear regression identified ALT (P = 0.0104) and AST (P = 0.0130) as predictors of viral compartmentalization. A total of 12 signature amino acids that distinguish liver from plasma E1/HVR1 were identified. One signature amino acid was shared by at least two individuals. These findings suggest that HCV compartmentalization is relatively common among patients co‐infected with HIV and HCV. These data also imply that evaluating viral diversity, including drug resistance patterns, in the serum/plasma only may not adequately represent viruses replicating with in the liver and, thus, deserves careful consideration in future studies. J. Med. Virol. 86:1332–1341, 2014. © 2014 Wiley Periodicals, Inc.
A systematic analysis of red lake pigments in French Impressionist and Post‐Impressionist paintings by surface‐enhanced Raman spectroscopy (SERS)
Authors: Pozzi Federica , van den Berg Klaas Jan , Fiedler Inge , Casadio Francesca
Published: May 2014

The Art Institute of Chicago (AIC) owns one of the largest and very finest collections of 19th century French Impressionist and Post‐Impressionist paintings in the world. While the palette of the Impressionists has been extensively characterized for what concerns both traditional and innovative inorganic pigments, to date, the identification of the red organic lakes – widely used for their intense, brilliant color – has posed an analytical challenge. In this work, firstly, surface‐enhanced Raman spectroscopy has been applied to the analysis of red lake paint reconstructions prepared according to 19th century historical recipes. Results demonstrated that dye identification can be successfully accomplished on Lee–Meisel colloids after hydrolysis with hydrofluoric acid, even when inorganic pigments, extenders, ground materials or binding media are associated with the red lake in the sample analyzed. Subsequently, the same protocol was used to examine samples from Manet, Pissarro, Renoir, Monet and Gauguin paintings in the AIC collection. Results showed the predominant use of madder and cochineal lakes, sometimes in combination, thus greatly enhancing our knowledge of the Impressionist usage of different types of red lakes. Copyright © 2014 John Wiley & Sons, Ltd.
Comparison of techniques for the isolation of volatiles from cashew apple juice
Authors: Sampaio Karina L , Biasoto Aline C T , Da Silva Maria Aparecida A P
Published: April 2014

BACKGROUND

The aim of this study was to compare the performance of the following techniques on the isolation of volatiles of importance for the aroma/flavor of fresh cashew apple juice: dynamic headspace analysis using PorapakQ® as trap, solvent extraction with and without further concentration of the isolate, and solid‐phase microextraction (fiber DVB/CAR/PDMS).

RESULTS

A total of 181 compounds were identified, from which 44 were esters, 20 terpenes, 19 alcohols, 17 hydrocarbons, 15 ketones, 14 aldehydes, among others. Sensory evaluation of the gas chromatography effluents revealed esters (n = 24) and terpenes (n = 10) as the most important aroma compounds.

CONCLUSION

The four techniques were efficient in isolating esters, a chemical class of high impact in the cashew aroma/flavor. However, the dynamic headspace methodology produced an isolate in which the analytes were in greater concentration, which facilitates their identification (gas chromatography–mass spectrometry) and sensory evaluation in the chromatographic effluents. Solvent extraction (dichloromethane) without further concentration of the isolate was the most efficient methodology for the isolation of terpenes. Because these two techniques also isolated in greater concentration the volatiles from other chemical classes important to the cashew aroma, such as aldehydes and alcohols, they were considered the most advantageous for the study of cashew aroma/flavor. © 2014 Society of Chemical Industry
Conservative surgery for ipsilateral breast tumor recurrence
Authors: Vila Jose , Garcia‐Etienne Carlos A. , Vavassori Andrea , Gentilini Oreste
Published: April 2014

The surgical and radiotherapeutic management of patients who develop an ipsilateral breast recurrence after primary conservative therapy remains controversial. Although current guidelines indicate the need for mastectomy for all recurrences, some reports in the literature suggest that a new conserving procedure (including repeat lumpectomy and second sentinel node biopsy) may be oncologically safe in selected patients. The rationale and current evidence for an appropriate second conservative approach are reviewed and discussed. J. Surg. Oncol. 2014 110:62–67. © 2014 Wiley Periodicals, Inc.
Partitioned analysis of flexible multibody systems using filtered linear finite element deformational modes
Authors: González José A. , Abascal Ramón , Park K.C.
Published: April 2014

This work presents a partitioned finite element formulation for flexible multibody systems, based on the floating frame (FF) approach, under the assumption of small deformations but arbitrarily large rotations of the bodies. In classical FF of reference methods, deformational modes are normally computed by modal analysis. In this approach, free‐floating modes are eliminated from the linear model using projection techniques and substituted by a complete set of non‐linear finite rotations. In this way, all deformational modes are retained, and no modal selection is needed. The main difference between this work and a classical FF of reference formulation is an algebraic separation of pure deformational modes from rigid‐body motions. The proposed methodology presents the following advantages. First, the position and orientation of the FF has no restriction and can be freely located in the body with identical results. Second, the formulation uses only the linear finite element matrices of a classical vibration problem; hence, they can be easily obtained from linear FEM packages. Third, no selection of modes is needed, all deformational modes are retained through the filtering process. And finally, thanks to the use of localized Lagrangian multipliers (LLM), a partitioned system is obtained that can be solved iteratively and in a distributed manner by available scalable solvers. Copyright © 2014 John Wiley & Sons, Ltd.
A level set approach for topology optimization with local stress constraints
Authors: Emmendoerfer Hélio , Fancello Eduardo Alberto
Published: April 2014

The purpose of this work is to present a level set‐based approach for the structural topology optimization problem of mass minimization submitted to local stress constraints. The main contributions are threefold. First, the inclusion of local stress constraints by means of an augmented Lagrangian approach within the level set context. Second, the proposition of a constraint procedure that accounts for a continuous activation/deactivation of a finite number of local stress constraints during the optimization sequence. Finally, the proposition of a logarithmic scaling of the level set normal velocity as an additional regularization technique in order to improve the minimization sequence. A set of benchmark tests in two dimensions achieving successful numerical results assesses the good behavior of the proposed method. In these examples, it is verified that the algorithm is able to identify stress concentrations and drive the design to a feasible local minimum. Copyright © 2014 John Wiley & Sons, Ltd.
Cyclic steady states of treaded rolling bodies
Authors: Govindjee Sanjay , Potter Trevor , Wilkening Jon
Published: April 2014

The analysis of spinning axisymmetric bodies undergoing finite deformation is useful for understanding the behavior of a wide variety of engineering systems – for example, rolling tires. However, progress beyond the axisymmetric case has been lacking. In this work, we present a methodology for the treatment of treaded rolling bodies by devising a Newton–Krylov shooting scheme for the computation of cyclic steady states of motion. The scheme advocated permits one to determine the entire transient (cyclically steady) motion of a spinning treaded body with consideration of viscoelasticity as well as contact. We demonstrate the viability of the method through three examples, (1) a viscoelastic cylinder with eight sinusoidal tread blocks, (2) a viscoelastic cylinder with 16 square tread blocks, and (3) a viscoelastic oval in which repeated contact and separation from a rigid plane excites distinct transient vibrational modes in the body during each cycle. For practical values of the viscoelastic relaxation time, the new approach is found to converge faster than the naïve approach of evolving an initial guess over many cycles until a cyclic steady state is reached. Copyright © 2014 John Wiley & Sons, Ltd.
A reduced local C0 discontinuous galerkin method for Kirchhoff plates
Authors: Huang Xuehai , Huang Jianguo
Published: May 2014

We propose and analyze a reduced local C0 discontinuous Galerkin (reduced LCDG) method with minimal penalization for Kirchhoff plate bending problems. The resulting linear system of the method can be solved efficiently by Gaussian elimination. Based on the key observation that the reduced LCDG method can be viewed as the localization of Hellan–Herrmann–Johnson method, we are inspired to use the techniques for dealing with the latter method to derive the well‐posedness and a priori error estimates of the reduced LCDG method. With the help of Zienkiewicz–Guzmán–Neilan element space, the a posteriori error analysis is also developed. Some numerical results are provided to demonstrate the theoretical estimates.© 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 1902–1930, 2014
Measuring persistence to hormonal therapy in patients with breast cancer: accounting for temporary treatment discontinuation
Authors: Huiart Laetitia , Ferdynus Cyril , Dell'Aniello Sophie , Bakiri Naciba , Giorgi Roch , Suissa Samy
Published: April 2014

Purpose

Several studies have been conducted to estimate persistence to hormonal therapy among women with breast cancer (BC). Most studies focus on first treatment discontinuation. Patients, however, can have numerous periods of treatment discontinuation or treatment exposure.

Our objective is to estimate persistence to tamoxifen in patients with BC while accounting for temporary treatment discontinuations and this by using multi‐state (MS) models.

Methods

A cohort of 10,806 women with BC having received at least one prescription of tamoxifen between 1998 and 2008 was constituted from the UK General Practice Research Database. We fitted a semi‐Markov model with three states to estimate the probability of being off treatment over a 5‐year period while accounting for temporary treatment discontinuations (transition between on treatment and off treatment) and competing risks (recurrence of BC or death).

Results

Non‐persistence, as estimated from the MS model, ranged from 12.1% (95% confidence interval [95%CI]: 9.2–15.1) at 1 year to 14.9% (95%CI: 11.7–18.1) at 5 years. Estimations of non‐persistence based on the Kaplan–Meier model were higher, i.e., 29.3% (95%CI: 28.1–30.6) at 5 years, as well as those obtained from a competing risk model, i.e., 24.0% (95%CI: 22.9–25.1). Most temporary discontinuations (94.7%) lasted less than 6 months.

Temporary treatment discontinuations are frequent and should be accounted for when measuring adherence to treatment. MS models can provide a useful framework for this sort of analysis insofar as they help describe patients’ complex behavior. This may help tailor interventions that improve persistence to hormonal therapy among women with BC. Copyright © 2014 John Wiley & Sons, Ltd.