bluuebunny/crossref_metadata_2025 huggingface dataset:
High methane emissions from thermokarst lakes in subarctic peatlands
Authors: Matveev Alex , Laurion Isabelle , Deshpande Bethany N. , Bhiry Najat , Vincent Warwick F.
Published: May 2016

The thawing and subsidence of frozen peat mounds (palsas) in permafrost landscapes results in the formation of organic‐rich thermokarst lakes. We examined the effects of palsa degradation on CH4 and CO2 emissions by comparing thermokarst lakes at two peatland locations in subarctic Québec, Canada: in the northern discontinuous permafrost region, and in southern sporadic permafrost where palsas are more rapidly degrading. The lakes were shallow (< 3 m) but stratified at both sites, and most had anoxic bottom waters. The surface waters at both sites were supersaturated in CH4 and CO2, and to a greater extent in the southern lakes, where the surface CH4 concentrations were up to 3 orders of magnitude above air equilibrium. Concentrations of CH4 and CO2 increased by orders of magnitude with depth in the southern lakes, however these gradients were less marked or absent in the North. Strong CH4 and CO2 emissions were associated with gas ebullition, but these were greatly exceeded by diffusive fluxes, in contrast to thermokarst lakes studied elsewhere. Also unusual relative to other studies to date, the surface concentrations of both gases increased as a linear function of water column depth, with highest values over the central, deepest portion of the lakes. Radiocarbon dating of ebullition gas samples showed that the CH4 had 14C‐ages from 760 yr to 2005 yr before present, while the CO2 was consistently younger. Peatland thermokarst lakes may be an increasingly important source of greenhouse gases as the southern permafrost limit continues to shift northwards.
Bioinspired Interface Engineering in Elastomer/Graphene Composites by Constructing Sacrificial Metal–Ligand Bonds
Authors: Huang Jing , Tang Zhenghai , Yang Zhijun , Guo Baochun
Published: May 2016

It remains a huge challenge to create advanced elastomers combining high strength and great toughness. Despite enhanced strength and stiffness, elastomeric nanocomposites suffer notably reduced extensibility and toughness. Here, inspired by the concept of sacrificial bonding associated with many natural materials, a novel interface strategy is proposed to fabricate elastomer/graphene nanocomposites by constructing a strong yet sacrificial interface. This interface is composed of pyridine‐Zn2+‐catechol coordination motifs, which is strong enough to ensure uniform graphene dispersion and efficient stress transfer from matrix to fillers. Moreover, they are sacrificial under external stress, which dissipates much energy and facilitates chain orientation. As a result, the strength, modulus, and toughness of the elastomeric composites are simultaneously strikingly enhanced relative to elastomeric bulk. This work suggests a promising methodology of designing advanced elastomers with exceptional mechanical properties by engineering sacrificial bonds into the interface.

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A summation‐integral type modification of Szász–Mirakjan operators
Authors: Mishra Vishnu Narayan , Gandhi R. B.
Published: May 2016

In this paper, we introduced a summation‐integral type modification of Szász–Mirakjan operators. Calculation of moments, density in some space, a direct result and a Voronvskaja‐type result, are obtained. Copyright © 2016 John Wiley & Sons, Ltd.
Maxwell's equations in an unbounded structure
Authors: Li Peijun , Zheng Gaofeng , Zheng Weiying
Published: May 2016

This paper is concerned with the mathematical analysis of the electromagnetic wave scattering by an unbounded dielectric medium, which is mounted on a perfectly conducting infinite plane. By introducing a transparent boundary condition on a plane surface confining the medium, the scattering problem is modeled as a boundary value problem of Maxwell's equations. Based on a variational formulation, the problem is shown to have a unique weak solution for a wide class of dielectric permittivity and magnetic permeability by using the generalized Lax–Milgram theorem. Copyright © 2016 John Wiley & Sons, Ltd.
Lossless error estimates for the stationary phase method with applications to propagation features for the Schrödinger equation
Authors: Ali Mehmeti Felix , Dewez Florent
Published: May 2016

We consider a version of the stationary phase method in one dimension of A. Erdélyi, allowing the phase to have stationary points of non‐integer order and the amplitude to have integrable singularities. After having completed the original proof and improved the error estimate in the case of regular amplitude, we consider a modification of the method by replacing the smooth cut‐off function employed in the source by a characteristic function, leading to more precise remainder estimates. We exploit this refinement to study the time‐asymptotic behaviour of the solution of the free Schrödinger equation on the line, where the Fourier transform of the initial data is compactly supported and has a singularity. We obtain asymptotic expansions with respect to time in certain space‐time cones as well as uniform and optimal estimates in curved regions, which are asymptotically larger than any space‐time cone. These results show the influence of the frequency band and of the singularity on the propagation and on the decay of the wave packets. Copyright © 2016 John Wiley & Sons, Ltd.
Analysis of planar microwave devices using higher order curl‐conforming triangular prismatic finite elements
Authors: Garcia‐Donoro Daniel , Ting Sioweng , Amor‐Martin Adrian , Garcia‐Castillo Luis E.
Published: May 2016

The evaluation of the accuracy and performance of a higher‐order curl‐conforming triangular prismatic finite element is carried out in this article. The triangular prismatic finite element proposed by the authors is tested by simulating real microwave devices in planar technology. The results obtained using this prismatic element are compared with those obtained using the finite element method reference commercial software HFSS that makes use of higher‐order tetrahedral finite elements. Conclusions about the use of this prismatic element for the analysis of planar microwave devices are given. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1794–1801, 2016
Multiband multistandard frequency synthesizer for mobile TV tuner with LC‐VCO by digital AAC
Authors: Lee Jae Kyung , Kim Young‐Jin , Cho Choon Sik
Published: May 2016

To improve the phase noise (PN) degradation from the tail current source, this article presents an inductor‐capacitor voltage‐controlled oscillator (LC‐VCO) with digitally controlled programmable low drop out. The digital automatic amplitude calibration (AAC) loop is successively implemented to make the voltage swing constant over 900–1940 MHz. A 40–970 MHz frequency synthesizer with switching dividers is implemented to support the operating frequency range of the multiband mobile TV tuners. The PN of −130 dBc/Hz @ 1 MHz offset is obtained at 474 MHz. The PN variation by the help of AAC loop is measured <2.4 dB over −40–85°C. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1838–1841, 2016
A compact internal antenna for LTE/WWAN mobile phone applications
Authors: Yu Cheng‐Chi , Yang Jiin‐Hwa , Chen Chang‐Chih
Published: May 2016

A compact multiband internal antenna is proposed for LTE/WWAN mobile phone application. The structure of proposed antenna is composed of a coupling feed L‐shaped monopole and a grounded meandered branch. The coupling feed L‐shaped monopole excites a widely operating band to cover the frequency range of 1750∼2525 MHz for the DCS/PCS/UMTS/LTE/WLAN operation. The grounded meandered branch excites the low frequency operation band to cover the frequency range of 675∼985 MHz for the LTE700/GSM operation. The antenna occupies a small volume of 4 × 14 × 45 mm3 only. The measured result of the 6 dB return loss meets for each operating band. Moreover, the antenna gain and efficiency are measured in good performances. The measured radiation patterns are similar to general monopole antenna. The characteristics of the proposed antenna make it attractive for slim mobile phone applications. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1834–1838, 2016
Efficiency optimization of WPT system with a planar receiver for mobile applications
Authors: Thuan Nguyen Van , Hyon Kang Seok , Won Jung Chang
Published: May 2016

This letter presents a wireless power transfer (WPT) system with a planar receiver for mobile applications. The proposed WPT system includes a source coil, a transmitter spiral (Tx coil), a rectangular receiver coil (Rx coil), and a rectangular load coil. In order to make a compact receiver, the Rx coil is placed in front of the load coil with a gap of 2 mm. In addition, the relation between the transfer efficiency of WPT system and the capacitance value of Rx coil is established. Experimental results show that by optimizing the capacitor embedded in Rx coil, it is capable of achieving a very high transfer efficiency. With an optimized capacitor Cx = 785 pF on the Rx coil, the transfer efficiency of the proposed system is comparable to a WPT system using a metamaterial (MTM) array. The proposed WPT system operates at 6.78 MHz. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1817–1819, 2016
Acceleration of monostatic shooting and bouncing ray method for inverse synthetic aperture radar image generation
Authors: Lee Yong‐Hee , Bae Ji‐Hoon , Kang Byung‐Soo , Lee Seung‐Jae , Kim Kyung‐Tae
Published: May 2016

The enhanced shooting and bouncing ray (SBR) technique based on the bistatic approximation, which is called the one‐shot inverse synthetic aperture radar (ISAR) technique, has been devised to accelerate the conventional monostatic SBR (CM‐SBR) technique, which is suitable for inverse synthetic aperture radar (ISAR) imaging. However, because of the bistatic approximation, this method results in the distortion of ISAR images. Therefore, to obtain an accurate image, radar returns should be obtained from the monostatic configuration. This paper describes a new method, the ray‐travel map (RTM), which accelerates the CM‐SBR technique while simultaneously considering both the CM‐SBR and the ISAR configuration. Then, we demonstrate that the proposed method can significantly enhance the speed of CM‐SBR, while providing accurate distortion‐free ISAR image. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1848–1855, 2016
Mimo antenna with high frequency selectivity and controllable bandwidth for band‐notched UWB applications
Authors: Huang Hui‐Fen , Xiao Shu‐Guang
Published: May 2016

A multiple‐input–multiple‐output (MIMO) antenna with high frequency selectivity and controllable bandwidth, is proposed for band‐notched ultrawideband (UWB) applications. In other words, it has a bandstop‐filter‐like response (second‐order notched band) at the aimed rejected band. It consists of two rectangular printed monopole (PM) elements and a simple stepped ground stub to enhance wideband isolation. For achieving the second‐order rejected band of the IEEE 802.11 wireless local area network (WLAN) band from 5.15 to 5.85 GHz centered at 5.5 GHz, two parasitic modified split‐ring resonators (PMSRRs) and two inverted L‐shaped branches (ILBs), are utilized. Measured results prove a bandwidth of S11 < −10 dB and S12 < −15 dB at 2.8–12 GHz excluding a rejection band of 5–5.95 GHz. Its size is only 32 × 26 mm2 on a cost‐effective FR4 substrate. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1886–1891, 2016
Resonances of electromagnetic oscillations in a spherical metal nanoparticle
Authors: Belyaev B.A. , Tyurnev V.V.
Published: May 2016

Electrodynamic analysis of plasma oscillations in a spherical metal nanoparticle is performed. It is shown that typical reduction in the frequency and quality factor of the resonances with increasing nanoparticle radius fades if the mode number grows. Depending on the particle radius, the resonant enhancement of the electric field might considerably either increase or decrease with increasing mode number. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1883–1886, 2016
Low insertion loss microstrip dualband lowpass‐bandpass filter with controllable passband frequencies
Authors: Chen Fu‐Chang , Shao Qiang
Published: May 2016

This letter proposes a novel dualband filter consisting of one lowpass passband and one bandpass passband. The dualband filter is realized using stub‐loaded transmission lines and stepped‐impedance stubs. The key merit of the filter configuration is that the lowpass and bandpass passband frequencies can be flexibly controlled by tuning the impedances and lengths of the transmission lines. Without coupling gap between the transmission lines, the new filter shows low insertion loss and easy for fabrication. To illustrate the concepts, a dualband lowpass‐bandpass filter is designed, fabricated, and measured. The cut‐off frequency of the lowpass filter is selected to be 1 GHz. The central frequency of the bandpass filter is chosen to be 5.2 GHz. Experimental measurements are in good agreement with both simulations and theoretical expectations. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1858–1861, 2016
A fast and accurate technique for FSS and antenna designs based on the social spider optimization algorithm
Authors: Oliveira P. S. , D'Assunção A. G. , Souza E. A. M. , Peixeiro C.
Published: May 2016

This paper presents a fast, accurate, and multifunctional electromagnetic optimization bioinspired technique that uses the social spider optimization algorithm (SSO). The proposed technique is applied to the design of a frequency selective surface (FSS), with Vicsek fractal patch elements, and an ultra wideband antenna (UWB), consisting of a ring monopole. In the proposed (synthesis) technique, the use of a database or the construction of a neural network is not required. The SSO algorithm communicates via scripts directly with the Ansoft HFSS software tool, enabling a good flexibility in the number of parameters to be optimized and reducing the required computation time. The accuracy and efficiency of the proposed technique is confirmed by comparison with experimental results and with other simulation techniques. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1912–1917, 2016
Wearable textile patch antenna fed by proximity coupling with increased bandwidth
Authors: Grilo Marcus , Hiroaki Seko Murilo , Salete Correra Fatima
Published: May 2016

This letter presents the design methodology of a textile rectangular patch antenna with increased bandwidth. The broadening of the antenna operating band is obtained by using a proximity coupling feed line cascaded to a quarter‐wave impedance transformer. The design parameters used to enhance the antenna bandwidth are the widths of the feed line and impedance transformer. The proposed design procedure has been applied to the design of four antennas centered at 2.45 GHz using denim substrate and conductive fabric. All antennas have the same patch dimensions, but they were designed using different values for the widths of the feed line and impedance transformer. The measured 10‐dB return loss bandwidth of the antenna prototypes are 11.2%, 13.4%, 17.0%, and 24.0%, in good agreement with simulated results. The effect of human body proximity and antenna curvature on the performance of the designed antennas has also been analyzed. The antenna configuration investigated has demonstrated to be able to increase the antenna operating band. The proposed design procedure is flexible, allowing the design of antennas with a variety of bandwidth values. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1906–1912, 2016
Increasing the bandwidth of a SiGe HBTLNA with minimum impact on noise figure
Authors: Bimana Abadahigwa , Sinha Saurabh
Published: May 2016

This paper introduces a matching technique for highly sensitive integrated broadband low‐noise amplifiers. Noise matching is achieved by the paralleling of identical input transistors. Impedance matching, based on reducing the number of components to the absolute minimum, is done by using the base‐collector capacitance as network element. Using a 0.13
m silicon‐germanium (SiGe) bipolar complementary metal oxide semiconductor process, simulation results indicate a maximum noise figure of 0.462 dB at room temperature and a return loss better than 10 dB from 300 MHz to 1.4 GHz. The technique demonstrates that SiGe heterojunction bipolar transistors can be used for cost‐effective applications in radio astronomy. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1937–1945, 2016
Coverage area enhancement of 2.4 GHz RFID system using switched beam patch antenna array
Authors: Zahid Kamran , Zahid Zeeshan , Siddique Kashif
Published: May 2016

The paper presents RF front end for coverage area enhancement of RFID systems operating at 2.4 GHz frequency (ISM band). The RF front end consists of a 1 × 4 circularly polarized micro‐strip patch antenna array having the capability of steering its beam in two discrete directions. Delay line phase shifters with two switching states have been used to steer the main beam. The switching is accomplished by using PIN diodes. Using this technique the angular coverage of 56° has been achieved. The antenna array has a peak gain of 8.9 dB. The design is simulated and optimized in antenna design software HFSS and fabricated on FR‐4 substrate. Simulated and measured results are in close agreement. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1945–1948, 2016
Suppression of spurious responses in microstrip half‐wavelength filters combining stagger tuning and resistive attenuation
Authors: Huang Frederick
Published: May 2016

Stagger tuning and resistive attenuation are combined to attenuate harmonic responses of microstrip filters with half‐wavelength resonators, extending the technique previously used for quarter‐wave resonators. In a measured filter with 0.93 GHz center frequency and 22% bandwidth, the worst spurious peak between 1.3 and 2.7 GHz is about 10 dB better than with stagger tuning alone, while the next two peaks at 2.75 and 3 GHz are suppressed by a further 5 dB. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1955–1957, 2016
Multiband monopole U‐slot patch antenna with truncated ground plane
Authors: Chandan  , Srivastava Toolika , Rai B. S.
Published: May 2016

In this article, a wideband microstrip‐fed monopole antenna with truncated ground plane is designed for multiband communication. The proposed antenna consists of a rectangular patch with two U‐shaped slots, and a ground plane with two rectangular slots. By cutting two U‐shaped slots in the radiating patch number of resonance is increased and more impedance bandwidth is achieved by cutting slots in ground plane which also improve impedance matching. The antenna is designed on the substrate FR4_epoxy to operate over four bands from 1.10–1.46 GHz, 2.23–2.91 GHz, 3.41–3.95 GHz, and 5.24–5.96 GHz with resonance frequencies of 1.21, 2.57, 3.61, and 5.60 GHz with % impedance bandwidth of 28.04, 26.45, 14.67, and 12.85% (for S11 < −10 dB). The antenna is simulated using software HFSS v13. Simulated and measured results are presented to validate the effectiveness of the proposed antenna for 1.2 GHz GPS, 2.4/5.5 GHz WLAN, and 3.5 WiMAX applications. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1949–1952, 2016
Diffraction of cylindrical waves by a perfectly conducting half‐screen: A modified theory of physical optics solution
Authors: Ziya Umul Yusuf
Published: May 2016

The scattering problem of waves, radiated by a line source, is investigated by the method of modified theory of physical optics. The solution is obtained for both of the Dirichlet and Neumann boundary conditions. Two dimensional modified theory of physical optics integral is considered, since the problem is symmetric according to one of the spatial coordinates. The scattering integral is directly evaluated and a new function is defined for the scattered fields. The mathematical properties of the function are studied. The total, geometrical optics and diffracted waves are analyzed numerically. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1996–2001, 2016
A transmissive/absorbing radome with double absorbing band
Authors: Yuan Xujin , Yuan Xiaofeng
Published: May 2016

A concise transmissive/absorbing radome principle model is presented, which realizes flat‐top wide‐band transmission band and two electromagnetic absorbing wide band located above and beneath the transmission band. Simulation indicates reflection signature of this radome structure could be reduced by over −10 dB out of transmission band. Frequency‐selective characters are achieved by one resistive FSS layer and two metallic FSS layers with nested square element, along with two dielectric spacer layers. An experimental‐demonstration sample plate fabrication and measurement testifies the model preliminarily. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2016–2019, 2016
A strategic model for state compliance verification
Authors: Listner Clemens , Niemeyer Irmgard , Canty Morton , Stein Gotthard
Published: May 2016

The theory of directed graphs and noncooperative games is applied to the problem of verification of State compliance to international treaties on arms control, disarmament and nonproliferation of weapons of mass destruction. Hypothetical treaty violations are formulated in terms of illegal acquisition paths for the accumulation of clandestine weapons, weapons‐grade materials or some other military capability. The paths constitute the illegal strategies of a sovereign State in a two‐person inspection game played against a multi‐ or international Inspectorate charged with compliance verification. The effectiveness of existing or postulated verification measures is quantified in terms of the Inspectorate's expected utility at Nash equilibrium. A prototype software implementation of the methodology and a case study are presented. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 260–271, 2016
Primary Cutaneous Lymphomas in Children and Adolescents
Authors: Ceppi Francesco , Pope Elena , Ngan Bo , Abla Oussama
Published: May 2016

Primary cutaneous lymphomas are rare in children and mostly represented by mycosis fungoides and CD30+ lymphoproliferative disorders. Most pediatric cutaneous lymphomas have similar clinical/pathological features as their adult counterparts, particularly the T‐cell subtypes. With regard to outcome, adult cutaneous mature T‐cell lymphomas have a tendency to progression, while this appears to be relatively infrequent in children. The outcome of cutaneous B‐cell lymphomas depends on subtype, with the B‐lymphoblastic entity being associated with similar outcomes to precursor B acute lymphoblastic leukemia, while there are insufficient data on other entities. The diagnosis and treatment of these patients require a close collaboration between experienced pediatric pathologists, dermatologists, and oncologists. Prospective collection of longitudinal clinical and biological data from children with these rare lymphomas is needed to better understand their biological and clinical behavior and to ultimately discover the best therapeutic strategies.
Safety and efficacy of recombinant factor VIIa by pediatric age cohort: reassessment of compassionate use and trial data supporting US label
Authors: Croteau Stacy E. , Nakar Charles , Neufeld Ellis J. , Shapiro Amy , Cooper David L.
Published: May 2016

Background

The relative safety and efficacy of recombinant activated coagulation factor VII (rFVIIa, NovoSeven® RT) across pediatric age cohorts is poorly defined. The objective of this analysis was to assess the safety and efficacy of rFVIIa in pediatric patients with congenital hemophilia with inhibitors (CHwI) in the clinical studies supporting the U.S. labeling.

Procedure

Pediatric data were derived from seven studies (five acute and two perioperative treatments) and pooled. All data were stratified by age (<2, 2 to <6, 6 to <12, and 12–16 years) and study category (acute treatment of bleeding episodes or surgery).

Results

The pediatric dataset included 172 patients; 144 received rFVIIa for the treatment of bleeding episodes and 28 for the control of bleeding perioperatively. Recombinant FVIIa was effective for 95.4% (1,026/1,076) of the evaluable bleeding episodes and had similar treatment effectiveness across pediatric age groups (range, 94.1–97.2%). The majority received doses of 90 mcg/kg. rFVIIa was effective in achieving perioperative hemostasis across pediatric age groups (range, 91–100%), with greater efficacy observed with the recommended (90 mcg/kg) versus lower dose (35 mcg/kg). A total of 88 pediatric patients experienced a total of 285 adverse drug reactions, similar in type to those reported among adult patients. A total of seven thrombotic events were recorded in seven pediatric patients; only one was confirmed related to rFVIIa upon individual case review.

Conclusions

rFVIIa is safe and effective in the treatment of bleeding episodes and prevention of periprocedure bleeding in CHwI with no apparent differences observed among pediatric age groups.
Enhancement of silicon solar cells by downshifting with Eu and Tb coordination complexes
Authors: Fix T. , Nonat A. , Imbert D. , Di Pietro S. , Mazzanti M. , Slaoui A. , Charbonnière L. J.
Published: May 2016

Luminescent lanthanide‐doped oxides, nanoparticles, nanocrystals, and coordination complexes are major tools in the fields of optical and laser materials, telecommunications, medical imaging, and fluoroimmunoassays. In particular, coordination complexes are efficient energy converters with high photostability, large ligand‐induced Stokes shifts, and tunable excitation and emission spectra. However, their application as light downshifting materials for solar cells has not yet been widely explored. This third generation solar cell concept enables to increase the efficiency of standard solar cells—such as Si or copper indium gallium (di)selenide (CIGS)—that have low performance for ultraviolet photons. The incorporation of such a converter in solar module encapsulants can provide a cheap and effective way to integrate photon conversion. Here, encapsulants functionalised by photon downshifting coordination complexes have been spin‐coated on silicon solar cells. For all the coordination complexes, an increase of the spectral response of the solar cells is observed in the ultraviolet region. In the best case, a relative increase of 8% of the conversion efficiency of the solar cell is observed. Copyright © 2016 John Wiley & Sons, Ltd.
Solvent network at the transition state in the solvolysis of hindered sulfonyl compounds
Authors: Iazykov Mykyta , Rublova Ludmila , Canle L. Moisés , Santaballa J. Arturo
Published: May 2016

Alcoholysis rates of unhindered benzenesulfonyl chlorides (X‐ArSO2Cl, X = H‐; 4‐Br‐; 4‐Me‐) are similar in methanol; the same behavior is also observed in ethanol, whereas the reactivity order in iso‐propanol is 4 Me‐ < H‐ < 4‐Br‐. On the other hand, alcoholysis of sterically hindered arenesulfonyl chlorides (X‐ArSO2Cl) (X = 2,4,6‐Me3‐3‐NO2‐; 2,6‐Me2‐4‐tBu‐; 2,4,6‐Me3‐; 2,3,5,6‐Me4‐; 2,4,6‐iPr3‐; 2,4‐Me2‐; 2,4,6‐(OMe)3‐) in all studied alcohols show a significant increase in reactivity, the so‐called positive steric effect.

Most of the substrates showed a reaction order b ~ 2 with respect to the nucleophile in methanol and ethanol, and b ~ 3 in iso‐propanol. The correlation between reactivity and the Kirkwood function (1/ξ) gives negative sensitivity (U) for all systems. All substrates showed high sensitivity to media nucleophilicity that depends on ΣσX.

Obtained results suggest the alcoholysis of benzenesulfonyl chlorides proceeds through SN2 mechanism where the transition state (TS) involves the participation of 2–3 alcohol molecules; such a TS can be cyclic, in the case of unbranched alcohols, or linear, for alcohols with bulkier hydrocarbon groups like iso‐propanol. To include the number of alcohol molecules playing such a role in the TS, the following terminology is proposed: cSN2sn for SN2 reactions involving n solvent molecules in a cyclic (c) TS, where “s” stands for the solvent and “n” is either the closest integer or half‐integer to the reaction order relative to the solvent or, in computational studies, the proposed number of solvent molecules taking part in the TS, whereas SN2sn is proposed when the TS is not cyclic. Copyright © 2016 John Wiley & Sons, Ltd.
Interest in initiating an early phase clinical trial: results of a longitudinal study of advanced cancer patients
Authors: Dunn Laura B. , Wiley Jim , Garrett Sarah , Hlubocky Fay , Daugherty Christopher , Trupin Laura , Munster Pamela , Dohan Daniel
Published: May 2016

Objective

Enhanced recruitment of patients with advanced cancer (ACP) to early phase (EP) trials is needed. However, selective recruitment may affect the kinds of patients who are recruited. To address whether ACP who initiate EP trial enrollment differ from those who do not, we prospectively surveyed ACP well in advance of potential trial recruitment and followed them over time to identify those who initiated the recruitment process.

Methods

EP trial initiation was defined as a patient being referred for screening to an active EP trial. Depression and anxiety were assessed with the Patient Health Questionnaire (PHQ‐9) and Generalized Anxiety Disorder Scale (GAD‐7), respectively. Demographic and disease characteristics, functional status, and patient preferences regarding decision making were examined as possible predictors of EP trial initiation.

Results

Of the 78 advanced cancer patients in the cohort studied, 21 (27%) initiated EP trial participation, while 57 (73%) did not. Of those who initiated this process, 14 (67%) went on to enroll in an EP study. Level of depression severity was associated with EP trial initiation, with rates of initiation nearly three times higher (35% vs. 12%, p = 0.054) among patients with minimal to mild levels of depression compared to those with moderate or higher levels of depression. EP trial initiation was not associated with demographic or socioeconomic variables, cancer type, functional status, quality of life, or decision‐making variables.

Conclusions

The presence of elevated depressive symptoms may be associated with the EP trial recruitment and enrollment processes. This possible relationship warrants further study. Copyright © 2016 John Wiley & Sons, Ltd.
Context and Implications Document for: Learner Engagement: A Review of Approaches in the Psychology of Education and Art Education
Authors: Kinsella Claire , Putwain David W. , Kaye Linda K.
Published: May 2016

This guide accompanies the following article: Claire Kinsella, David W. Putwain and Linda K. Kaye, Learner Engagement: A Review of Approaches in the Psychology of Education and Art Education, Review of Education, DOI:10.1002/rev3.3063
The Sterically Demanding Thiosilyl Group SSi(SiMe3)3 as a Ligand in Transition Metal Chemistry
Authors: Kotsch Matthias , Gienger Christian , Schrenk Claudio , Schnepf Andreas
Published: May 2016

The increasing number of metalloid clusters, synthesized in the last couple of years, gives new insights into the formation process of metals or semi‐metals. Metalloid clusters of the transition metals, especially the coinage metals are thereby of particular interest and the number of structurally characterized metalloid gold clusters has increased over the last decade. Most of these clusters are stabilized via aryl thiolate ligands. Herein, the synthesis and crystal structures of the lithium and potassium salts of the bulky SSi(SiMe3)3 ligand are presented together with the synthesis of suitable MI precursors (M = Cu, Ag, Au) for further build‐up reactions to metalloid clusters.
Use of animals with partially known ancestries in scientifically managed breeding programs
Authors: Willis Kevin , Lacy Robert C.
Published: May 2016

Animals with only partially known ancestry present a problem for population managers because it can be difficult to determine their relative genetic value to the population. So long as their ancestry is not completely unknown, population management software such as PMx can calculate a mean kinship for these animals, but that mean kinship is calculated such that there is no decrease in relative genetic value or “penalty” for only partially known ancestry. However, there is a longer‐term genetic cost to having animals with only partially known ancestry in the population, and thus it is appropriate to “penalize” animals with partially known ancestry to some extent. The challenge is determining the correct “penalty” which will serve to decrease the percent unknown ancestry in subsequent generations while not causing excessive selection against the known ancestry of the animal. A new parameter of relative genetic value is developed which takes into account both an animal's mean kinship as well as its percent known ancestry. The method used in PMx to calculate the mean kinships also in general overestimates the inbreeding coefficients of offspring of animals with partially known ancestry when the known parents share a common ancestor, but can underestimate inbreeding if common ancestors exist within the unknown portion of the pedigree. This may result in population managers selecting less suitable pairs for breeding in an attempt to avoid an apparent higher level of inbreeding. A parameter is developed that adjusts the inbreeding coefficient to more accurately reflect the likely inbreeding coefficient of potential offspring. Zoo Biol. 35:319–325, 2016. © 2016 Wiley Periodicals, Inc.
Cholic Acid‐Derived Facial Surfactants with Long Side‐Chain Quaternary Ammonium: Synthesis and Antimicrobial Activity Study
Authors: Zhou Lanxiang , Li Yang , Li Shuangshuang , Shen Xinliang , Wang Cunde
Published: May 2016

Four cholic acid cationic surfactants containing a flexible long aliphatic chain were synthesized efficiently. A long aliphatic chain was introduced first on the side‐chain carboxyl of cholic acid by one‐pot condensation reaction of cholic acid and C12–C18 amines using DCC (Dicyclohexylcarbodiimide) and HOBt (N‐hydroxybenzotrizole) as condensation agents for the formation of an amide framework. Then reduction of the amide and quaternization gave a cationic group for strengthening hydrophilicity. This strategy offered a very straightforward and efficient method for access to the designed surfactants in good overall yields. Preliminary results show that an increase both in the length of the hydrophobic tail and in the number of charged groups lowered the CMC of cholic acid‐derived cationic surfactants. Cholic acid‐based cationic surfactants containing a flexible longer aliphatic chain and a quaternary ammonium had the highest antimicrobial activity.
Combined Urea Complexation and Argentated Silica Gel Column Chromatography for Concentration and Separation of PUFAs from Tuna Oil: Based on Improved DPA Level
Authors: Mu Hongyan , Jin Jun , Xie Dan , Zou Xiaoqiang , Wang Xiaosan , Wang Xingguo , Jin Qingzhe
Published: May 2016

Eicosapentaenoic acid (EPA, 20:5n‐3), docosapentaenoic acid (DPA) isomers (22:5n‐6 and 22:5n‐3) and docosahexaenoic acid (DHA, 22:6n‐3) derived from tuna oil were concentrated by three stages of urea fractionation at various crystallization temperatures and different fatty acid/urea ratios. Thereafter, polyunsaturated fatty acids concentrate containing comparatively enriched DPA levels was purified by argentated silica gel column chromatography. A product containing 22.2 ± 0.6 % EPA, 4.6 ± 0.0 % DPAn‐6, 5.9 ± 0.1 % DPAn‐3 and 42.3 ± 1.2 % DHA was obtained at 1:1.6 fatty acid/urea ratio (w/w) by crystallization at −8 °C for 16 h, −20 °C for 8 h, and −8 °C for 16 h. A DPA isomer concentrate containing 26.1 ± 0.5 % DPAn‐6 and 22.3 ± 0.4 % DPAn‐3 was achieved by argentated silica gel chromatography in the 6 % acetone/n‐hexane solvent fraction (v/v), and the recovery of both fatty acids was 66.1 ± 3.2 and 70.7 ± 2.2 %, respectively. Furthermore, 91.9 ± 2.5 % EPA and 99.5 ± 2.1 % DHA with recoveries of 47.8 ± 2.0 and 56.7 ± 3.3 %, respectively, were obtained in various fractions.
Determination of the Best Parameter for Defining the Hemodynamic Significance of an Iliac Artery Stenosis Detected on Computed Tomography Angiography
Authors: Lougheed Nick , Jaskolka Jeff , Beecroft Rob , Menezes Ravi
Published: May 2016

Purpose

The purpose of this study was to determine the best parameter, derived from computed tomography angiography (CTA) for accurate prediction of a hemodynamically significant stenosis of the common or external iliac artery.

Methods

A retrospective keyword search was performed on the Radiology Information System at our tertiary academic medical centre. Reports from January 2008 to September 2013 were searched using the keywords iliac, stenosis, and pressure. Patients who had both and CTA and a pelvic angiogram with pressure measurements obtained across a potential stenosis were selected. Using 3D postprocessing software (TeraRecon, Foster City, CA), the CTAs were analysed for the following parameters of each lesion: minimum diameter of stenosis, minimum cross-sectional area of stenosis, percent narrowing of vessel diameter, and percent reduction in vessel area. The percent stenosis was calculated in reference to the outer diameter at the point of maximal narrowing and also in reference to a normal segment of vessel more distal to the stenosis. These parameters were then compared with the measured pressure gradient using receiver-operating characteristic analysis and the Mann-Whitney U test to determine which best predicted a significant stenosis, defined as a greater than 10% drop in systolic pressure across a lesion.

Results

One hundred and two stenoses in 83 patients (26 women, 57 men; 47-88 years old) were identified. Mean diameter of the stenosis was 2.8 mm for significant stenosis compared to 3.8 mm in nonsignificant stenoses ( P = .005). Mean minimum area for significant stenoses was 11.8 mm2 compared to 17.22 mm2 for nonsignificant stenoses ( P = .032) No other variables showed a significant difference between significant and nonsignificant stenoses. A minimum diameter of ≤4.0 mm at the level of a stenosis is 92% sensitive and 48% specific for predicting a hemodynamically significant iliac artery stenosis, with a positive predictive value of 88%.

Conclusions

A simple measurement of the minimum diameter of an iliac artery at the level of stenosis is the best predictor of the hemodynamic significance of a stenosis in the common or external iliac artery.
Gamma-ray pulsar light curves as probes of magnetospheric structure
Authors: Harding A. K.
Published: May 2016

The large number of ${\it\gamma}$-ray pulsars discovered by the Fermi Gamma-Ray Space Telescope since its launch in 2008 dwarfs the handful that were previously known. The variety of observed light curves makes possible a tomography of both the ensemble-averaged field structure and the high-energy emission regions of a pulsar magnetosphere. Fitting the ${\it\gamma}$-ray pulsar light curves with model magnetospheres and emission models has revealed that most of the high-energy emission, and the particles acceleration, takes place near or beyond the light cylinder, near the current sheet. As pulsar magnetosphere models become more sophisticated, it is possible to probe magnetic field structure and emission that are self-consistently determined. Light curve modelling will continue to be a powerful tool for constraining the pulsar magnetosphere physics.
An Extant Instance of ‘Q’
Authors: Garrow Alan
Published: May 2016

The mainstream approaches to the Synoptic Problem all agree: there are no extant instances of Q. The shape of ‘Q’ changes, however, if, as proposed in the companion article, ‘Streeter's “Other” Synoptic Solution: The Matthew Conflator Hypothesis’, Matthew sometimes conflates Luke with Luke's own source. Where this happens Luke's source qualifies as an instance of ‘Q’ – inasmuch as it preserves sayings of Jesus used, ultimately, by both Luke and Matthew. This fresh conception of ‘Q’ opens up the possibility that examples of ‘Q’ are, after all, available. An extant text meeting this description is Didache 1.2–5a.
Transition from community dwelling to retirement village in older adults: cognitive functioning and psychological health outcomes
Authors: HOLLAND CAROL , BOUKOUVALAS ALEXIS , WALLIS STUART , CLARKESMITH DANIELLE , COOKE RICHARD , LIDDELL LEANNE , KAY AMANDA
Published: May 2016

Supported living and retirement villages are becoming a significant option for older adults with impairments, with independence concerns or for forward planning in older age, but evidence as to psychological benefits for residents is sparse. This study examined the hypothesis that the multi-component advantages of moving into a supported and physically and socially accessible ‘extra-care’ independent living environment will impact on psychological and functioning measures. Using an observational longitudinal design, 161 new residents were assessed initially and three months later, in comparison to 33 older adults staying in their original homes. Initial group differences were apparent but some reduced after three months. Residents showed improvement in depression, perceived health, aspects of cognitive function and reduced functional limitations, while controls showed increased functional limitations (worsening). Ability to recall specific autobiographical memories, known to be related to social problem solving, depression and functioning in social relationships, predicted change in communication limitations, and cognitive change predicted changes in recreational limitations. Change in anxiety and memory predicted change in depression. Findings suggest that older adults with independent living concerns who move to an independent but supported environment can show significant benefits in psychological outcomes and reduction in perceived impact of health on functional limitations in a short period. Targets for focused rehabilitation are indicated, but findings also validate development of untargeted general supportive environments.
Residential care and care to community-dwelling parents: out-selection, in-selection and diffusion of responsibility
Authors: VAN DEN BROEK THIJS , DYKSTRA PEARL A.
Published: May 2016

Research suggests that adult children are less likely to provide care to community-dwelling parents when beds in residential care settings are more widely available. The underlying mechanisms are not well understood. Drawing on data from the Survey of Health, Ageing and Retirement in Europe (SHARE) on 1,214 impaired parent–child dyads from 12 countries, we find that adult children are less likely to provide care in countries where beds in residential care settings are more widely available because (a) parents’ care needs are less severe in such countries (out-selection hypothesis) and (b) adult children and impaired parents are less likely to share a household in such countries (in-selection hypothesis). Finally (c), after taking these two factors into account, adult children remain less likely to provide care in countries where beds in residential care settings are more widely available (diffusion of responsibility hypothesis). Plausibly, being able to rely on residential care undermines adult children's sense of urgency to step in and provide care to their parents.
A survey of direct methods for sparse linear systems
Authors: Davis Timothy A. , Rajamanickam Sivasankaran , Sid-Lakhdar Wissam M.
Published: May 2016

Wilkinson defined a sparse matrix as one with enough zeros that it pays to take advantage of them.1This informal yet practical definition captures the essence of the goal of direct methods for solving sparse matrix problems. They exploit the sparsity of a matrix to solve problems economically: much faster and using far less memory than if all the entries of a matrix were stored and took part in explicit computations. These methods form the backbone of a wide range of problems in computational science. A glimpse of the breadth of applications relying on sparse solvers can be seen in the origins of matrices in published matrix benchmark collections (Duff and Reid 1979a, Duff, Grimes and Lewis 1989a, Davis and Hu 2011). The goal of this survey article is to impart a working knowledge of the underlying theory and practice of sparse direct methods for solving linear systems and least-squares problems, and to provide an overview of the algorithms, data structures, and software available to solve these problems, so that the reader can both understand the methods and know how best to use them.
On the computation of measure-valued solutions
Authors: Fjordholm Ulrik S. , Mishra Siddhartha , Tadmor Eitan
Published: May 2016

A standard paradigm for the existence of solutions in fluid dynamics is based on the construction of sequences of approximate solutions or approximate minimizers. This approach faces serious obstacles, most notably in multi-dimensional problems, where the persistence of oscillations at ever finer scales prevents compactness. Indeed, these oscillations are an indication, consistent with recent theoretical results, of the possible lack of existence/uniqueness of solutions within the standard framework of integrable functions. It is in this context that Young measures – parametrized probability measures which can describe the limits of such oscillatory sequences – offer the more general paradigm ofmeasure-valued solutionsfor these problems.

We present viable numerical algorithms to compute approximate measure-valued solutions, based on the realization of approximate measures as laws of Monte Carlo sampled random fields. We prove convergence of these algorithms to measure-valued solutions for the equations of compressible and incompressible inviscid fluid dynamics, and present a large number of numerical experiments which provide convincing evidence for the viability of the new paradigm. We also discuss the use of these algorithms, and their extensions, in uncertainty quantification and contexts other than fluid dynamics, such as non-convex variational problems in materials science.
Evidence for a bimodal bilingual disadvantage in letter fluency
Authors: GIEZEN MARCEL R. , EMMOREY KAREN
Published: May 2016

Many bimodal bilinguals are immersed in a spoken language-dominant environment from an early age and, unlike unimodal bilinguals, do not necessarily divide their language use between languages. Nonetheless, early ASL–English bilinguals retrieved fewer words in a letter fluency task in their dominant language compared to monolingual English speakers with equal vocabulary level. This finding demonstrates that reduced vocabulary size and/or frequency of use cannot completely account for bilingual disadvantages in verbal fluency. Instead, retrieval difficulties likely reflect between-language interference. Furthermore, it suggests that the two languages of bilinguals compete for selection even when they are expressed with distinct articulators.