bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal effects of groundwater flow through subarctic fens: A case study based on field observations and numerical modeling
Authors: Sjöberg Ylva , Coon Ethan , K. Sannel A. Britta , Pannetier Romain , Harp Dylan , Frampton Andrew , Painter Scott L. , Lyon Steve W.
Published: February 2016

Modeling and observation of ground temperature dynamics are the main tools for understanding current permafrost thermal regimes and projecting future thaw. Until recently, most studies on permafrost have focused on vertical ground heat fluxes. Groundwater can transport heat in both lateral and vertical directions but its influence on ground temperatures at local scales in permafrost environments is not well understood. In this study we combine field observations from a subarctic fen in the sporadic permafrost zone with numerical simulations of coupled water and thermal fluxes. At the Tavvavuoma study site in northern Sweden, ground temperature profiles and groundwater levels were observed in boreholes. These observations were used to set up one‐ and two‐dimensional simulations down to 2 m depth across a gradient of permafrost conditions within and surrounding the fen. Two‐dimensional scenarios representing the fen under various hydraulic gradients were developed to quantify the influence of groundwater flow on ground temperature. Our observations suggest that lateral groundwater flow significantly affects ground temperatures. This is corroborated by modeling results that show seasonal ground ice melts 1 month earlier when a lateral groundwater flux is present. Further, although the thermal regime may be dominated by vertically conducted heat fluxes during most of the year, isolated high groundwater flow rate events such as the spring freshet are potentially important for ground temperatures. As sporadic permafrost environments often contain substantial portions of unfrozen ground with active groundwater flow paths, knowledge of this heat transport mechanism is important for understanding permafrost dynamics in these environments.
River stage influences on uranium transport in a hydrologically dynamic groundwater‐surface water transition zone
Authors: Zachara John M. , Chen Xingyuan , Murray Chris , Hammond Glenn
Published: February 2016

A well‐field within a uranium (U) plume in the groundwater‐surface water transition zone was monitored for a 3 year period for water table elevation and dissolved solutes. The plume discharges to the Columbia River, which displays a dramatic spring stage surge resulting from snowmelt. Groundwater exhibits a low hydrologic gradient and chemical differences with river water. River water intrudes the site in spring. Specific aims were to assess the impacts of river intrusion on dissolved uranium (Uaq), specific conductance (SpC), and other solutes, and to discriminate between transport, geochemical, and source term heterogeneity effects. Time series trends for Uaq and SpC were complex and displayed large temporal and well‐to‐well variability as a result of water table elevation fluctuations, river water intrusion, and changes in groundwater flow directions. The wells were clustered into subsets exhibiting common behaviors resulting from the intrusion dynamics of river water and the location of source terms. Hot‐spots in Uaq varied in location with increasing water table elevation through the combined effects of advection and source term location. Heuristic reactive transport modeling with PFLOTRAN demonstrated that mobilized Uaq was transported between wells and source terms in complex trajectories, and was diluted as river water entered and exited the groundwater system. While Uaq time‐series concentration trends varied significantly from year‐to‐year as a result of climate‐caused differences in the spring hydrograph, common and partly predictable response patterns were observed that were driven by water table elevation, and the extent and duration of river water intrusion.
Optimization and Analysis of Conjugated Polymer Side Chains for High‐Performance Organic Photovoltaic Cells
Authors: Kim Ji‐Hoon , Wood Sebastian , Park Jong Baek , Wade Jessica , Song Myungkwan , Yoon Sung Cheol , Jung In Hwan , Kim Ji‐Seon , Hwang Do‐Hoon
Published: February 2016

Optimization and analysis of conjugated polymer side chains for high‐performance organic photovoltaic cells (OPVs) reveal a critical relationship between the chemical structure of the side chains and photovoltaic properties of polymer‐based bulk heterojunction OPVs. In particular, the impact of the alkyl side chain length on the π‐bridging (thienothiophene, TT) unit is considered by designing and synthesizing a series of benzodithiophene derivatives (BDT(T)) and thieno[3,2‐b]thiophene‐π‐bridged thieno[3,4‐c]pyrrole‐4,6(5H)‐dione (ttTPD) alternating copolymers, PBDT(T)‐(R2)ttTPD, with alkyl chains of varying length on the TT unit. Using a combination of 2D X‐ray diffraction, Raman spectroscopy, and electrical device characterization, it is elucidated in detail how these subtle changes to the chemical structure affect the molecular conformation, thin film molecular packing, blend film morphology, optoelectronic properties, and hence overall photovoltaic performance. For copolymers employing both the alkoxy or alkylthienyl‐substituted BDT motifs, it is found that octyl side chains on TT unit yield the maximum degree of molecular backbone coplanarity and result in the highest quality of molecular packing and optimized hole mobility. Inverted devices fabricated using this PBDTT‐8ttTPD: polymer/[6,6]‐phenyl‐C71‐butylic acid methyl ester active layer show a maximum power conversion efficiency (PCE) of 8.7% with large area cells (0.64 cm2) maintaining a PCE of 7.5%.
Hyperbranched Polymers with High Transparency and Inherent High Refractive Index for Application in Organic Light‐Emitting Diodes
Authors: Wei Qiang , Pötzsch Robert , Liu Xiaoling , Komber Hartmut , Kiriy Anton , Voit Brigitte , Will Paul‐Anton , Lenk Simone , Reineke Sebastian
Published: February 2016

Hyperbranched polyvinylsulfides have been prepared through a facile, metal‐free, radical induced “A2+B3” thiol‐yne polymerization of 1,3,5‐tris(naphthalylethynyl) benzene and 1,4‐dithiolbenzene with three different input ratios. The resulting polymers exhibit excellent optical properties like high transparency and very high refractive index (RI) of up to 1.7839, combined with high thermal stability (Td5% up to 420 °C) and excellent solution processability. These properties make them ideal candidates as high RI polymeric materials (HRIP) in connection with light out‐coupling schemes for organic light‐emitting diodes (OLEDs). A series of hyperbranched HRIPs with varying monomer compositions have been compared in their optical properties. Finally, phosphorescent monochrome OLEDs are fabricated on top of HRIP layers to test the compatibility of HRIPs with state‐of‐the‐art OLEDs. The results show that the HRIPs do not deteriorate the performance of the OLEDs while maintaining external quantum efficiencies of over 20% for phosphorescent red OLEDs. These results open a pathway toward alternative, low‐cost, and scalable out‐coupling concepts through refractive index matching of the OLED materials and the HRIPs presented.
Efficiency and Stability Enhancement in Perovskite Solar Cells by Inserting Lithium‐Neutralized Graphene Oxide as Electron Transporting Layer
Authors: Agresti Antonio , Pescetelli Sara , Cinà Lucio , Konios Dimitrios , Kakavelakis George , Kymakis Emmanuel , Carlo Aldo Di
Published: February 2016

This work proposes a new perovskite solar cell structure by including lithium‐neutralized graphene oxide (GO‐Li) as the electron transporting layer (ETL) on top of the mesoporous TiO2 (m‐TiO2) substrate. The modified work‐function of GO after the intercalation of Li atoms (4.3 eV) exhibits a good energy matching with the TiO2 conduction band, leading to a significant enhancement of the electron injection from the perovskite to the m‐TiO2. The resulting devices exhibit an improved short circuit current and fill factor and a reduced hysteresis. Furthermore, the GO‐Li ETL partially passivates the oxygen vacancies/defects of m‐TiO2 by resulting in an enhanced stability under prolonged 1 SUN irradiation.
Protonated Phosphazenes: Structures and Hydrogen‐Bonding Organocatalysts for Carbonyl Bond Activation
Authors: Jardel Damien , Davies Clotilde , Peruch Frédéric , Massip Stéphane , Bibal Brigitte
Published: February 2016

The synthesis and application of protonated phosphazeniums as hydrogen‐bond donor groups was demonstrated in the solid state and in solution. In particular, their catalytic activity was shown in the activation of the carbonyl group within cyclic esters, using a benchmark reaction, that is, in the ring‐opening polymerization of lactide and valerolactone, in the presence of a basic co‐catalyst. The reactions proceed differently depending on monomers and/or phosphazenium salts. The impact of catalysts and reactants steric hindrance upon the outcome of the reaction is then highlighted and discussed.

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Progress and Challenges in Transfer of Large‐Area Graphene Films
Authors: Chen Yi , Gong Xiao‐Lei , Gai Jing‐Gang
Published: February 2016

Graphene, the thinnest, strongest, and stiffest material with exceptional thermal conductivity and electron mobility, has increasingly received world‐wide attention in the past few years. These unique properties may lead to novel or improved technologies to address the pressing global challenges in many applications including transparent conducting electrodes, field effect transistors, flexible touch screen, single‐molecule gas detection, desalination, DNA sequencing, osmotic energy production, etc. To realize these applications, it is necessary to transfer graphene films from growth substrate to target substrate with large‐area, clean, and low defect surface, which are crucial to the performances of large‐area graphene devices. This critical review assesses the recent development in transferring large‐area graphene grown on Fe, Ru, Co, Ir, Ni, Pt, Au, Cu, and some nonmetal substrates by using various synthesized methods. Among them, the transfers of the most attention kinds of graphene synthesized on Cu and SiC substrates are discussed emphatically. The advances and the main challenges of each wet and dry transfer method for obtaining the transferred graphene film with large‐area, clean, and low defect surface are also reviewed. Finally, the article concludes the most promising methods and the further prospects of graphene transfer.
Molecular Orientation‐Dependent Bias Stress Stability in Bottom‐Gate Organic Transistors Based on an n‐Type Semiconducting Polymer
Authors: Kang Boseok , Moon Byungho , Choi Hyun Ho , Song Eunjoo , Cho Kilwon
Published: February 2016

Despite remarkable advances in the performances of organic field‐effect transistors (OFETs) in recent years, the bias stability of OFET devices remains a critical obstacle to their commercial use. The microstructural origins of charge traps inside OFET devices are not yet clearly understood, and investigating these origins presents an important challenge. The unique electrical properties of an n‐type semiconducting polymer, poly[[N,N′‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5′‐(2,2′‐bithiophene)] (P(NDI2OD‐T2)), are explored here to study the correlation between the microstructures of polymer semiconductor thin films and the bias stability of an OFET. It is demonstrated that although the charge carrier mobilities in a series of devices may be similar, the bias stress stabilities can differ significantly, depending on the molecular orientations of the semiconducting thin films. A higher degree of bias stress stability is attained in the P(NDI2OD‐T2) FETs prepared with face‐on thin‐film structures compared to the bias stress stability attained in the edge‐on film structures. Further experimental evidence suggests that the aliphatic alkyl chains in edge‐on‐oriented P(NDI2OD‐T2) films present a hurdle to vertical charge transport and induce large numbers of bipolarons during bias stress, in contrast with the face‐on structured thin films.
Iridium Oxide‐Assisted Plasmon‐Induced Hot Carriers: Improvement on Kinetics and Thermodynamics of Hot Carriers
Authors: Hung Sung‐Fu , Xiao Fang‐Xing , Hsu Ying‐Ya , Suen Nian‐Tzu , Yang Hong‐Bin , Chen Hao Ming , Liu Bin
Published: February 2016

Plasmonic nanostructures are capable of driving photocatalysis through absorbing photons in the visible region of the solar spectrum. Unfortunately, the short lifetime of plasmon‐induced hot carriers and sluggish surface chemical reactions significantly limit their photocatalytic efficiencies. Moreover, the thermodynamically favored excitation mechanism of plasmonic photocatalytic reactions is unclear. The mechanism of how the plasmonic catalyst could enhance the performance of chemical reaction and the limitation of localized surface plasmon resonance devices is proposed. In addition, a design is demonstrated through co‐catalyst decorated plasmonic nanoparticles Au/IrOX upon a semiconductor nanowire‐array TiO2 electrode that are able to considerably improve the lifetime of plasmon‐induced charge‐carriers and further facilitate the kinetics of chemical reaction. A thermodynamically favored excitation with improved kinetics of hot carriers is revealed through electrochemical studies and characterization of X‐ray absorption spectrum. This discovery provides an opportunity to efficiently manage hot carriers that are generated from metal nanostructures through surface plasmon effects for photocatalysis applications.
Ni and Co Segregations on Selective Surface Facets and Rational Design of Layered Lithium Transition‐Metal Oxide Cathodes
Authors: Yan Pengfei , Zheng Jianming , Zheng Jiaxin , Wang Zhiguo , Teng Gaofeng , Kuppan Saravanan , Xiao Jie , Chen Guoying , Pan Feng , Zhang Ji‐Guang , Wang Chong‐Min
Published: February 2016

The chemical processes occurring on the surface of cathode materials during battery cycling play a crucial role in determining battery's performance. However, the understanding of such surface chemistry is far from clear due to the complexity of redox chemistry during battery charge/discharge. Through intensive aberration corrected STEM investigation on ten layered oxide cathode materials, two important findings on the pristine oxides are reported. First, Ni and Co show strong plane selectivity when building up their respective surface segregation layers (SSLs). Specifically, Ni‐SSL is exclusively developed on (200)m facet in Li–Mn‐rich oxides (monoclinic C2/m symmetry) and on (012)h facet in Mn–Ni equally rich oxides (hexagonal R‐3m symmetry), while Co‐SSL has a strong preference to (20−2)m plane with minimal Co‐SSL also developed on some other planes in Li–Mn‐rich cathodes. Structurally, Ni‐SSLs tend to form spinel‐like lattice while Co‐SSLs are in a rock‐salt‐like structure. Second, by increasing Ni concentration in these layered oxides, Ni and Co SSLs can be suppressed and even eliminated. The findings indicate that Ni and Co SSLs are tunable through controlling particle morphology and oxide composition, which opens up a new way for future rational design and synthesis of cathode materials.
Disentangling the associations between parental BMI and offspring body composition using the four‐component model
Authors: Devakumar Delan , Grijalva‐Eternod Carlos , Cortina‐Borja Mario , Williams Jane , Fewtrell Mary , Wells Jonathan
Published: February 2016

Objectives

This study sets out to investigate the intergenerational associations between the body mass index (BMI) of parents and the body composition of their offspring.

Methods

The cross‐sectional data were analyzed for 511 parent–offspring trios from London and south‐east England. The offspring were aged 5–21 years. Parental BMI was obtained by recall and offspring fat mass and lean mass were obtained using the four‐component model. Multivariable regression analysis, with multiple imputation for missing paternal values was used. Sensitivity analyses for levels of non‐paternity were conducted.

Results

A positive association was seen between parental BMI and offspring BMI, fat mass index (FMI), and lean mass index (LMI). The mother's BMI was positively associated with the BMI, FMI, and LMI z‐scores of both daughters and sons and of a similar magnitude for both sexes. The father's BMI showed similar associations to the mother's BMI, with his son's BMI, FMI, and LMI z‐scores, but no association with his daughter. Sensitivity tests for non‐paternity showed that maternal coefficients remained greater than paternal coefficients throughout but there was no statistical difference at greater levels of non‐paternity.

Conclusions

We found variable associations between parental BMI and offspring body composition. Associations were generally stronger for maternal than paternal BMI, and paternal associations appeared to differ between sons and daughters. In this cohort, the mother's BMI was statistically significantly associated with her child's body composition but the father's BMI was only associated with the body composition of his sons. Am. J. Hum. Biol. 28:524–533, 2016. © 2016 The Authors American Journal of Human Biology Published by Wiley Periodicals, Inc.
Phonon‐polariton entrapment in homogenous surface phonon cavities
Authors: Yudistira Didit , Boes Andreas , Dumas Benjamin , Rezk Amgad R. , Yousefi Morteza , Djafari‐Rouhani Bahram , Yeo Leslie Y. , Mitchell Arnan
Published: February 2016

Surface phonon cavities that are homogenous in both mechanical and dielectric properties are reported. The cavities are formed by the placement of a defect of a single domain within periodic domain inversion of single crystal piezoelectric lithium niobate that exhibits surface phononic bandgap through the phonon‐polariton coupling. Surface cavity resonances are observed within the bandgap, which manifest in entrapment of phonon‐polariton within the defect. In addition to demonstrating that the observed resonances are non‐radiative and decoupled to bulk radiation, which is critical for high Q cavities, it is also shown the possibility to tune the surface cavity resonance spectra simply by varying the defect width. Such an ability to excite surface cavity resonance that is non‐radiative with simultaneous localization of the electric field together with the advantage of a cavity that is physically formed from a completely monolithic and uniform material offers unique opportunities for widespread applications for example in actuation, detection, and phonon lasing that can be fully integrated with other physical systems such as quantum acoustics, photonics, and microfluidics.

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Validating Eaton's Hypothesis: Cubane as a Benzene Bioisostere
Authors: Chalmers Benjamin A. , Xing Hui , Houston Sevan , Clark Charlotte , Ghassabian Sussan , Kuo Andy , Cao Benjamin , Reitsma Andrea , Murray Cody‐Ellen P. , Stok Jeanette E. , Boyle Glen M. , Pierce Carly J. , Littler Stuart W. , Winkler David A. , Bernhardt Paul V. , Pasay Cielo , De Voss James J. , McCarthy James , Parsons Peter G. , Walter Gimme H. , Smith Maree T. , Cooper Helen M. , Nilsson Susan K. , Tsanaktsidis John , Savage G. Paul , Williams Craig M.
Published: February 2016

Pharmaceutical and agrochemical discovery programs are under considerable pressure to meet increasing global demand and thus require constant innovation. Classical hydrocarbon scaffolds have long assisted in bringing new molecules to the market place, but an obvious omission is that of the Platonic solid cubane. Eaton, however, suggested that this molecule has the potential to act as a benzene bioisostere. Herein, we report the validation of Eaton's hypothesis with cubane derivatives of five molecules that are used clinically or as agrochemicals. Two cubane analogues showed increased bioactivity compared to their benzene counterparts whereas two further analogues displayed equal bioactivity, and the fifth one demonstrated only partial efficacy. Ramifications from this study are best realized by reflecting on the number of bioactive molecules that contain a benzene ring. Substitution with the cubane scaffold where possible could revitalize these systems, and thus expedite much needed lead candidate identification.
Acid Treatment Enables Suppression of Electron–Hole Recombination in Hematite for Photoelectrochemical Water Splitting
Authors: Yang Yi , Forster Mark , Ling Yichuan , Wang Gongming , Zhai Teng , Tong Yexiang , Cowan Alexander J. , Li Yat
Published: February 2016

We report a strategy for efficient suppression of electron–hole recombination in hematite photoanodes. Acid‐treated hematite showed a substantially enhanced photocurrent density compared to untreated samples. Electrochemical impedance spectroscopy studies revealed that the enhanced photocurrent is partly due to improved efficiency of charge separation. Transient absorption spectroscopic studies coupled to electrochemical measurements indicate that, in addition to improved bulk electrochemical properties, acid‐treated hematite has significantly decreased surface electron–hole recombination losses owing to a greater yield of the trapped photoelectrons being extracted to the external circuit.
Halide–Amine Co‐Passivated Indium Phosphide Colloidal Quantum Dots in Tetrahedral Shape
Authors: Kim Kyungnam , Yoo Dongsuk , Choi Hyekyoung , Tamang Sudarsan , Ko Jae‐Hyeon , Kim Sungwoo , Kim Yong‐Hyun , Jeong Sohee
Published: February 2016

Wet chemical synthesis of covalent III‐V colloidal quantum dots (CQDs) has been challenging because of uncontrolled surfaces and a poor understanding of surface–ligand interactions. We report a simple acid‐free approach to synthesize highly crystalline indium phosphide CQDs in the unique tetrahedral shape by using tris(dimethylamino) phosphine and indium trichloride as the phosphorus and indium precursors, dissolved in oleylamine. Our chemical analyses indicate that both the oleylamine and chloride ligands participate in the stabilization of tetrahedral‐shaped InP CQDs covered with cation‐rich (111) facets. Based on density functional theory calculations, we propose that fractional dangling electrons of the In‐rich (111) surface could be completely passivated by three halide and one primary amine ligands per the (2×2) surface unit, satisfying the 8‐electron rule. This halide–amine co‐passivation strategy will benefit the synthesis of stable III‐V CQDs with controlled surfaces.
Monitoring Tyrosinase Expression in Non‐metastatic and Metastatic Melanoma Tissues by Scanning Electrochemical Microscopy
Authors: Lin Tzu‐En , Bondarenko Alexandra , Lesch Andreas , Pick Horst , Cortés‐Salazar Fernando , Girault Hubert H.
Published: February 2016

Although tremendous progress has been made in the diagnosis of melanoma, the identification of different stages of malignancy in a reliable way remains challenging. Current strategies rely on optical monitoring of the concentration and spatial distribution of specific biomarkers. State‐of‐the‐art optical methods can be affected by background‐color interference and autofluorescence. We overcame these shortcomings by employing scanning electrochemical microscopy (SECM) to map the prognostic indicator tyrosinase (TyR) in non‐metastatic and metastatic melanoma tissues by using soft‐stylus microelectrodes. Electrochemical readout of the TyR distribution was enabled by adapting an immunochemical method. SECM can overcome the limitations of optical methods and opens unprecedented possibilities for improved diagnosis and understanding of the spatial distribution of TyR in different melanoma stages.
Synthesis and characterization of PMMA composites activated with starch for immobilization of L‐asparaginase
Authors: Ulu Ahmet , Koytepe Suleyman , Ates Burhan
Published: February 2016

Poly (methyl methacrylate) (PMMA)–starch composites were prepared by emulsion polymerization technique for L‐asparaginase (L‐ASNase) immobilization as highly activated support. The hydroxide groups on the prepared composites offer a very simple, mild and firm combination for enzyme immobilization. The pure PMMA and PMMA‐starch composites were characterized as structural, thermal and morphological. PMMA‐starch composites were found to have better thermal stability and more hydrophilic character than pure PMMA. L‐ASNase was immobilized onto PMMA‐starch composites contained the different ratio of starch (1, 3, 5, and 10 wt %). Immobilized L‐ASNase showed better performance as compared to the native enzyme in terms of thermal stability and pH. Km value of immobilized enzyme decreased approximately eightfold compared with the native enzyme. In addition to, immobilized L‐ASNase was found to retain 60% of activity after 1‐month storage period at 4 °C. Therefore, PMMA‐starch composites can be provided more advantageous in terms of enzymatic affinity, thermal, pH and storage stability as L‐ASNase immobilization matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43421.
What anatomy is clinically useful and when should we be teaching it?
Authors: Leveritt Simon , McKnight Gerard , Edwards Kimberley , Pratten Margaret , Merrick Deborah
Published: February 2016

Anatomy teaching, once thought of as being the cornerstone of medical education, has undergone much change in the recent years. There is now growing concern for falling standards in medical graduates' anatomical knowledge, coupled with a reduction in teaching time and appropriately qualified teaching staff. With limited contact hours available to teach this important discipline, it is essential to consider what anatomy is taught within the medical curriculum to ensure it is fit for clinical practice. The views of medical students, junior doctors, and consultants were obtained from the University of Nottingham and the Trent Deanery in Nottingham, United Kingdom, to establish what core anatomical knowledge they feel medical students should study and assimilate during preclinical training. All participants felt strongly that medical students should be adept at interpreting modern diagnostic images before entering their clinical placement or specialty. Respondents proposed more teaching emphasis should be placed on specific anatomical areas (including lymphatic drainage and dermatome innervation) and illustrated other areas where less detailed teaching was appropriate. Recommendations from our study highlight a need for greater clinical emphasis in anatomy teaching during preclinical years. To successfully achieve this, it is essential that clinicians become integrally involved in the design and delivery of future medical undergraduate anatomy courses. Anat Sci Educ 9: 468–475. © 2016 American Association of Anatomists.
Decentralized Observer Design for a Class of Nonlinear Uncertain Large Scale Systems with Lumped Perturbations
Authors: Liu Wen‐Jeng
Published: February 2016

Many valuable properties of the state feedback method can not be applied to some class of control systems while some of the system states cannot be measured directly. An attractive alternative approach is to make good use of a state observer. In this paper, a new decentralized sliding mode observer (DSMO) is proposed for a class of nonlinear uncertain large‐scale systems (LSS) with lumped perturbations based on the sliding mode control (SMC) theory. Our main result presented here is that we introduce a new switching term to the traditional LSS observer design for a class of large‐scale system to generate a new decentralized sliding mode observer. The generalized matrix inverse concept is adopted to avoid using the un‐measurable state and the global reaching condition of the sliding mode for each error subsystem is guaranteed. The stability of each equivalent error subsystem is verified based on the strictly positive real concept. It also shows that the investigated uncertain large‐scale systems still possesses the property of insensitivity to the lumped perturbations as does the traditional linear system. Moreover, the state transformation approach is no longer needed as there is no longer concern about the problems of finding a suitable transformation or indirect estimated states, since the proposed DSMO is not based on the transformed system model. Finally, a numerical example with a series of computer simulations is given to demonstrate the validity of the proposed decentralized sliding mode observer.
Graph‐Based Dwell Time Computation Methods for Discrete‐Time Switched Linear Systems
Authors: İlhan Ferruh , Karabacak Özkan
Published: February 2016

Analytical computation methods are proposed for evaluating the minimum dwell time and the average dwell time guaranteeing the asymptotic stability of a discrete‐time switched linear system whose switchings are assumed to respect a given directed graph. The minimum and average dwell time can be found using the graph that governs the switchings, and the associated weights. This approach, which is used in a previous work for continuous‐time systems having non‐defective subsystems, has been adapted to discrete‐time switched systems and generalized to allow defective subsystems. Moreover, we present a novel method to improve the dwell time estimation in the case of bimodal switched systems. In this method, scaling algorithms to minimize the condition number have been used to give better minimum dwell time and average dwell time estimates.
A Scanpath Analysis of the Risky Decision‐Making Process
Authors: Zhou Lei , Zhang Yang‐Yang , Wang Zuo‐Jun , Rao Li‐Lin , Wang Wei , Li Shu , Li Xingshan , Liang Zhu‐Yuan
Published: February 2016

In the field of eye tracking, scanpath analysis can reflect the sequential and temporal properties of the cognitive process. However, the advantages of scanpath analysis have not yet been utilized in the study of risky decision making. We explored the methodological applicability of scanpath analysis to test models of risky decision making by analyzing published data from the eye‐tracking studies of Su et al. (2013); Wang and Li (2012), and Sun, Rao, Zhou, and Li (2014). These studies used a proportion task, an outcome‐matched presentation condition, and a multiple‐play condition as the baseline for comparison with information search and processing in the risky decision‐making condition. We found that (i) the similarity scores of the intra‐conditions were significantly higher than those of the inter‐condition; (ii) the scanpaths of the two conditions were separable; and (iii) based on an inspection of typical trials, the patterns of the scanpaths differed between the two conditions. These findings suggest that scanpath analysis is reliable and valid for examining the process of risky decision making. In line with the findings of the three original studies, our results indicate that risky decision making is unlikely to be based on a weighting and summing process, as hypothesized by the family of expectation models. The findings highlight a new methodological direction for research on decision making. Copyright © 2016 John Wiley & Sons, Ltd.
Host manipulation by cancer cells: Expectations, facts, and therapeutic implications
Authors: Tissot Tazzio , Arnal Audrey , Jacqueline Camille , Poulin Robert , Lefèvre Thierry , Mery Frédéric , Renaud François , Roche Benjamin , Massol François , Salzet Michel , Ewald Paul , Tasiemski Aurélie , Ujvari Beata , Thomas Frédéric
Published: February 2016

Similar to parasites, cancer cells depend on their hosts for sustenance, proliferation and reproduction, exploiting the hosts for energy and resources, and thereby impairing their health and fitness. Because of this lifestyle similarity, it is predicted that cancer cells could, like numerous parasitic organisms, evolve the capacity to manipulate the phenotype of their hosts to increase their own fitness. We claim that the extent of this phenomenon and its therapeutic implications are, however, underappreciated. Here, we review and discuss what can be regarded as cases of host manipulation in the context of cancer development and progression. We elaborate on how acknowledging the applicability of these principles can offer novel therapeutic and preventive strategies. The manipulation of host phenotype by cancer cells is one more reason to adopt a Darwinian approach in cancer research.
A novelty strategy for the fast analysis of sulfonamide antibiotics in fish tissue using magnetic separation with high‐performance liquid chromatography–tandem mass spectrometry
Authors: Li Jincheng , Liu Huan , Zhang Jing , Liu Yang , Wu Lidong
Published: February 2016

A simple, fast and low‐cost extraction method with high‐performance liquid chromatography–tandem mass spectrometry (HPLC‐MS/MS) determination was developed on sulfonamide antibiotics (SAs) in fish tissue. Magnetic separation was first introduced into the rapid sample preparation procedure combined with acetonitrile extraction for the analysis of SAs. Partitioning was rapidly achieved between acetonitrile solution and solid matrix by applying an external magnetic field. Acetonitrile solution was collected and concentrated under a nitrogen stream. The residue was redissolved with 1‰ formic acid aqueous solution and defatted with n‐hexane before analysis. The recoveries of SAs were in the range of 74.87–104.74%, with relative standard deviations <13%. The limits of quantification and the limits of detection for SAs ranged from 5.0 to 25.0 μg kg−1 and from 2.5 to 10.0 μg kg−1, respectively. The presented extraction method proved to be a rapid method which only took 20 min for one sample preparation procedure. Copyright © 2016 John Wiley & Sons, Ltd.
mTester—Mobile learning system
Authors: Popović Oliver , Marković Dragan S. , Popović Ranko
Published: February 2016

In the 21st century, education represents a key factor of economic and social development of a community. The majority of traditional methods intended for education are no longer suitable for it, since they are unable to meet the students’ needs. Mobile learning represents a new educational channel, which allows access from any place at any time. In this paper, an overview of various forms of education is provided, concepts of mobile learning are discussed, educational mobile applications are analyzed, and the design and the prototype of a mobile application intended for learning, called mTester, is described. Finally, the paper presents a case study of mobile learning use, conducted at the Business School of Applied Studies in Blace, Serbia. The first results show an improvement in the realization of courses and in the students’ final grades. © 2016 Wiley Periodicals, Inc. Comput Appl Eng Educ 24:412–420, 2016; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21719
Polymers and Kinetic Resolutions: The Insolubility of It All
Authors: Clark Robert W. , Akhani Ravish K. , Wiskur Sheryl L.
Published: February 2016

Kinetic resolution is a powerful technique to obtain enantioenriched compounds. A major drawback to conventional kinetic resolutions is that the final purification step to isolate the stereoenriched compounds usually employs chromatography, which is costly and difficult to perform on an industrial scale. Recent advances have demonstrated the applicability of polymer supports as a means of separating enantiomerically enriched starting materials from products in kinetic resolutions by having one enantiomer attached to the polymer and the other in solution. Herein, several approaches are reviewed in which either homogenous or heterogeneous macromolecules are employed to facilitate a chromatography‐free isolation of stereoenriched compounds. Kinetic resolutions employing enzymatic, transition‐metal, or small‐molecule‐catalyzed reactions by using polymeric materials will be discussed.
Exhaust emissions and fuel economy improvements through thermal performance control in a novel three‐way catalytic converter
Authors: Litto Rajab , Mmbaga Joseph P. , Hayes Robert E. , Plati Stefano , Blagojevic Voislav , Subject Paul
Published: February 2016

This paper reports an investigation into the performance of a multi‐chamber catalytic converter (MCCC). The MCCC design uses internal insulation layers within a standard automotive catalytic converter to control the radial propagation of thermal energy. By retaining more energy within the monolith core, the emissions are reduced over the drive cycle, allowing for a reduction of precious metals use and a smaller catalytic converter. An additional benefit is a reduction in back pressure as a result of suppressing turbulence within the converter, which translates into an improvement in fuel economy of up to 15 %.
Comparison of cancer survival trends in the United States of adolescents and young adults with those in children and older adults
Authors: Keegan Theresa H.M. , Ries Lynn A.G. , Barr Ronald D. , Geiger Ann M. , Dahlke Deborah Vollmer , Pollock Bradley H. , Bleyer W. Archie ,   for the National Cancer Institute Next Steps for Adolescent and Young Adult Oncology Epidemiology Working Group
Published: February 2016

BACKGROUND

With prior reports indicating a lack of progress in survival improvement in older adolescents and young adults (AYAs) aged 15 to 39 years with cancer compared with both younger and older patients with cancer, the current analysis provides an update of survival trends of cancers among AYAs, children, and older adults.

METHODS

Data from the National Cancer Institute Surveillance, Epidemiology, and End Results database for 13 regions were used to ascertain survival trends of the 34 most frequent cancers diagnosed in AYAs compared with children and older adults.

RESULTS

As of 2002 through 2006, the 5‐year relative survival rate for all invasive cancers in AYAs was 82.5% (standard error, 0.2%). In AYAs, 14 cancers demonstrated evidence of a statistically significant improvement in their 5‐year relative survival since 1992. Survival improved less in AYAs than in children for acute myeloid leukemia and medulloblastoma. Fourteen cancers had survival improvements that were found to be less in AYAs compared with older adults, including hepatic carcinoma, acute myeloid leukemia, high‐grade astrocytoma, acute lymphocytic leukemia, pancreatic carcinoma, low‐grade astrocytoma, gastric carcinoma, renal carcinoma, cancer of the oral cavity and pharynx, Hodgkin lymphoma, ovarian cancer, fibromatous sarcoma, other soft tissue sarcoma, and thyroid carcinoma.

CONCLUSIONS

Improvements in the survival of several cancer types that occur frequently in AYAs are encouraging. However, survival does not appear to be improving to the same extent in AYAs as in children or older adults for several cancers. Further investment in exploring the distinct biology of tumors in this age group, and of their hosts, must be a priority in AYA oncology. Cancer 2016;122:1009–1016. © 2016 American Cancer Society
Gold Nanoparticle@Polyhedral Oligomeric Silsesquioxane Hybrid Scaffolds in Microfluidic Format – Highly Efficient and Green Catalytic Platforms
Authors: Scholder Pascal , Hafner Martina , Hassel Achim W. , Nischang Ivo
Published: February 2016

We report on the preparation of new hybrid organic–inorganic multiporous monolithic capillary columns carrying gold nanoparticles of 5, 10, 50, and 100 nm size and their use as flow‐through catalytic platforms for aqueous liquid‐phase reduction reactions. We found that the flow‐through performance of the reactors depends not only on the size of the gold nanoparticles but also on the interplay of the pore size of the scaffolds and the catalytically available gold surface within the system, that is, loading an increased number of gold nanoparticles of smaller size does not necessarily result in strictly improved performance. This indicates the importance of the interplay between the nanopore size of the scaffolds and the catalytically active gold surface existing within the system. Demonstration of the highly efficient catalytic flow‐through operation within seconds and the repeated use of the reactors without loss of performance indicates their excellent suitability as microfluidic device elements.
Manipulation of milk fatty acid composition in lactating cows: Opportunities and challenges
Authors: Kliem Kirsty E. , Shingfield Kevin J.
Published: February 2016

Public health policies recommend a population wide decrease in the consumption of saturated fatty acids (SFA) to lower the incidence of cardiovascular and metabolic diseases. In most developed countries, milk and dairy products are the major source of SFA in the human diet. Altering milk fat composition offers the opportunity to lower the consumption of SFA without requiring a change in eating habits. Supplementing the diet of lactating cows with oilseeds, plant oils and marine lipids can be used to replace the SFA in milk fat with monounsaturated fatty acids (MUFA), and to a lesser extent, polyunsaturated fatty acids (PUFA). Due to ruminal metabolism, the decreases in milk SFA are also accompanied by increases in trans fatty acids (TFA), including conjugated isomers. The potential to lower SFA, enrich cis MUFA and PUFA, and alter the abundance and distribution of individual TFA in milk differs according to oil source, form of lipid supplement and degree of oilseed processing, and the influence of other components in the diet. The present review summarises recent evidence on changes in milk fat composition that can be achieved using dietary lipid supplements and highlights the challenges to commercial production of modified milk and dairy products. A meta‐analysis on the effects of oilseeds on milk fatty acid composition is also presented.

Practical applications: Milk and dairy products are the major source of SFA in the diet in most developed countries. Including oilseeds, plant oils, and to a lesser extent, marine lipids in the diet of lactating cows can replace SFA with MUFA and PUFA in milk offering a mechanism to lower SFA consumption in human populations. Understanding the sources of variation in milk fat composition responses, and adjusting other ingredients in the diet to accommodate lipid supplements offers the opportunity to consistently produce milk with an altered fatty acid composition. However, commercialisation of dedicated supply chains will depend on whether the added costs of production and segregation of modified milk for processing can be recovered at retail.

Dairy products are the major source of saturated fatty acids in diets of developed countries. There are various dietary strategies that can be employed at the dairy cow level to alter milk fat fatty acid composition, but it is important to understand variations in cow response to these interventions to consistently produce milk with altered fatty acid composition.
Regioselective Multicomponent Synthesis of 2,4,6‐Trisubstituted Phenols from Fischer Alkynyl Carbene Complexes
Authors: López Julio , de la Cruz Fabiola N. , Flores‐Conde María Inés , Flores‐Álamo Marcos , Delgado Francisco , Tamariz Joaquín , Vázquez Miguel A.
Published: February 2016

A series of 2,4,6‐trisubstituted phenols 7a–7p has been prepared in moderate to good yields (23–77 %) by a retro‐Diels–Alder reaction from hindered tricyclic alcohols 6a–6q, using mild acidic conditions. The tricyclic alcohols were obtained by reduction of highly functionalized cyclohexadienones 5a–5q, which in turn were regioselectively prepared under mild conditions in high yields by treatment of a series of stable chromium(0) and tungsten(0) Fischer dienyl carbenes 4a–4g with different terminal alkynes 3a–3l. Carbenes 4a–4g were prepared by a [4+2] cycloaddition of alkynylethoxy carbene complexes 1a–1g with 1,2,3,4,5‐pentamethylcyclopentadiene (2). In a complementary route, compounds 5a–5q were also obtained by a multicomponent reaction in yields similar to those obtained in the multistep process (25–84 %), starting from 1a–1g, 2, and 3a–3l. The phenol products have a wide range of potential applications, and may be useful intermediates for further transformations.
Single‐state Q‐learning for self‐organised radio resource management in dual‐hop 5G high capacity density networks
Authors: Jiang Tao , Zhao Qiyang , Grace David , Burr Alister G. , Clarke Tim
Published: February 2016

In this paper, a dual‐hop wireless backhaul and small cell access network has been exploited with effective spectrum sharing to provide 1 Gb/s/km2 ultra‐high capacity density for 5G ultra‐dense network deployments. We develop a single‐state Q‐learning‐based radio resource management algorithm for dynamic spectrum access creating a self‐organised network. It intelligently utilises the instantaneous spectrum observation information from spectrum sensing or a database to learn long‐term optimised decisions based on historical information of the system. The conventional Q‐learning algorithm with state‐action pairs has been simplified to a stateless format and applied in a fully distributed manner on individual data file transmissions, which reduces the complexity of the learning model and improves the applicability of Q‐learning algorithms to self‐organised wireless networks. The results show that not only does the proposed algorithm completely remove the requirement for frequency planning but it also improves the convergence, Quality of Service and system capacity substantially by achieving higher link capacity on both access and backhaul networks. Copyright © 2016 John Wiley & Sons, Ltd.
Probabilistic Forecasts of Wind Power Generation by Stochastic Differential Equation Models
Authors: Møller Jan Kloppenborg , Zugno Marco , Madsen Henrik
Published: February 2016

The increasing penetration of wind power has resulted in larger shares of volatile sources of supply in power systems worldwide. In order to operate such systems efficiently, methods for reliable probabilistic forecasts of future wind power production are essential. It is well known that the conditional density of wind power production is highly dependent on the level of predicted wind power and prediction horizon. This paper describes a new approach for wind power forecasting based on logistic‐type stochastic differential equations (SDEs). The SDE formulation allows us to calculate both state‐dependent conditional uncertainties as well as correlation structures. Model estimation is performed by maximizing the likelihood of a multidimensional random vector while accounting for the correlation structure defined by the SDE formulation. We use non‐parametric modelling to explore conditional correlation structures, and skewness of the predictive distributions as a function of explanatory variables. Copyright © 2015 John Wiley & Sons, Ltd.
Frequency of chromosome 17 polysomy in relation to CEP17 copy number in a large breast cancer cohort
Authors: Koudelakova Vladimira , Trojanec Radek , Vrbkova Jana , Donevska Sandra , Bouchalova Katerina , Kolar Zdenek , Varanasi Lakshman , Hajduch Marian
Published: February 2016

Eligibility to anti‐HER2 therapy for breast tumors strictly depends on demonstrating HER2 overexpression (by immunohistochemistry) or HER2 gene amplification by in situ hybridization (ISH), usually defined by the ratio of HER2 gene to chromosome 17 centromere (CEP17) copies. However, the CEP17 copy number increase (CNI) has been proven responsible for misleading HER2 FISH results and recent small cohort studies suggest that chromosome 17 polysomy is actually very rare. Here we investigated by FISH the frequency of true chromosome 17 polysomy in a consecutive cohort of 5,477 invasive breast cancer patients. We evaluated and selected the LSI 17p11.2 probe for chromosome 17 enumeration on a training cohort of 67 breast cancer samples (CEP17 ≥ 2.5). LSI 17p11.2 was used in the 297/5,477 patients from the validation cohort displaying CEP17 CNI (CEP17 ≥ 3.0). Using HER2/17p11.2 scoring criteria, 37.3%/1.5% patients initially classified as equivocal/non‐amplified were reclassified as amplified. For a more accurate assessment of chromosome 17 and ploidy in the samples, we tested six markers located on chromosome 17 and centromeric regions of chromosome 8 (CEP8) and 11 (CEP11) in 67 patients with CEP17 and LSI 17p11.2 CNI. True polysomy (hyperdiploidy) according to these markers was found in 0.48% of cases (24/5,020). CEP8 and CEP11 CNI (≥3.0) was more frequent in the hyperdiploid than CEP17 non‐polysomic group (55.6% vs. 6.1% and 25% vs. 2.3%, respectively). Our results suggest that chromosome 17 polysomy is a rare event found in <1% breast cancer cases and that polysomy of other chromosomes frequently occurs with chromosome 17 polysomy. © 2016 Wiley Periodicals, Inc.