bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of Noncovalent Interactions in the Efficiency of Dendrimers in Catalysis
Authors: Caminade Anne-Marie
Published: March 2019

Dendrimers are nanometric macromolecules constituted of repetitive branched units, arranged radially around a central core. They are synthesized step-by-step, generally using a divergent process from this core. Dendrimers have many properties and, among them, catalysis is a major field. Two main area are studied, on the one hand the search for a positive “dendrimer effect,” i.e. an increase in catalytic efficiency when the size of the dendrimer increases, and on the other the encapsulation of catalytically active nanoparticles inside dendrimers. In both cases, noncovalent interactions are involved. This chapter discusses the important role played by noncovalent interactions in the properties of dendrimers in catalysis. The first part concerns the dendrimer effect, then a short section considers noncovalently formed catalytic dendrimers and the final part concerns dendrimers encapsulating catalytic nanoparticles.
Baeyer–Villiger Oxidation Promoted by Noncovalent Interactions
Authors: Martins Nuno M. R. , Martins Luísa M. D. R. S.
Published: March 2019

The relative complexity of noncovalent interactions has made them challenging to study. Nevertheless, theory and modelling have now reached the stage that allows their physical origins to be explained and reliable insight to be gained into their effects on chemical transformations. This chapter discusses the influence of coordination and noncovalent interactions in Baeyer–Villiger oxidations. These attractive forces can be powerful tools in the formation/stabilization of intermediates and in controlling the product outcome of a reaction.
Noncovalent Immobilization of Catalysts on Electrode Surfaces
Authors: Johnson Katie J. , Prather Keaton V. , Blakemore James D.
Published: March 2019

Molecular metal complexes and other redox-active species can be usefully incorporated into functional devices by attachment or immobilization on electrodes as solid supports. Stable adhesion of the complexes to electrode surfaces can be driven by covalent or noncovalent interactions. This chapter surveys the use of polyaromatic hydrocarbon moieties, chiefly the pyrene group, to immobilize redox-active species noncovalently onto electrode surfaces. Synthetic incorporation of pyrenyl groups onto core catalyst structures is shown to be attractive for its simplicity and it is generally effective in enabling studies of surface-immobilized redox chemistry and catalysis. Efforts reported in the literature to improve stability, electron-transfer kinetics and long-term catalyst viability are specifically highlighted. A summary and outlook section provides a brief discussion of key challenges to the field and opportunities for future developments in this rapidly evolving area.
Noncovalent Interactions in Olefin Polymerization Catalysis Promoted by Transition Metals
Authors: D'Alterio Massimo Christian , de Rosa Claudio , Talarico Giovanni
Published: March 2019

Two case histories are reported where noncovalent interactions play an important role in olefin polymerization catalyzed by transition metals. In the first example, by using DFT calculations, the influence of α-agostic interactions on the stereoselectivity of propene insertion reactions and their contribution to developing new models for the isotactic stereocontrol achieved with nonmetallocene catalysts are considered. In the second example, experimental and theoretical results aimed at explaining the role of noncovalent interactions (such as F⋯H or F⋯M, where M = metal center) in living olefin polymerization promoted by Group 4 nonmetallocene systems and also the chain-branching formation of polyethylene obtained with late transition metals are summarized.
Mechanochemical Activation and Catalysis
Authors: Kopylovich Maximilian N. , Ribeiro Ana P. C. , Alegria Elisabete C. B. A.
Published: March 2019

Chemical transformations induced by mechanical force in solids are remarkable since they facilitate syntheses that are normally difficult to achieve in solution and thus allow the preparation of new molecules and materials or drastic improvements of the yields and selectivities. In many cases, the noncovalent interactions (NCIs) with mechanochemical treatment differ significantly from those which occur in analogous solvent-assisted processes. Moreover, if a “mechanocatalyst” is introduced into the system, it can additionally alter the NCIs, bond energies and properties of the reaction intermediates. As result, the outcome of many mechanocatalytic reactions can be very different in terms of efficiency or even reaction pathways compared with the traditional solution-based procedures or noncatalytic mechanochemical processes. Accordingly, in this chapter, certain mechanocatalytic reactions in which the NCIs play a key role are overviewed and discussed. Additionally, an overview of some experimental techniques used to study mechanochemical activation and the respective NCIs is also provided.
New insights for the valorisation of glycerol over MgO catalysts in the gas-phase
Authors: Smith Louise R. , Smith Paul J. , Mugford Karl S. , Douthwaite Mark , Dummer Nicholas F. , Willock David J. , Howard Mark , Knight David W. , Taylor Stuart H. , Hutchings Graham J.
Published: March 2019

Aqueous glycerol solutions of up to 50 wt% were reacted over magnesium oxide catalysts at temperatures greater than 300 °C, the reactivity of which was compared to catalyst-free reactions.
G-Quadruplex binding optimization by gold(iii) insertion into the center of a porphyrin
Authors: Pipier Angélique , De Rache Aurore , Modeste Coralie , Amrane Samir , Mothes-Martin Emmanuelle , Stigliani Jean-Luc , Calsou Patrick , Mergny Jean-Louis , Pratviel Geneviève , Gomez Dennis
Published: March 2019

Gold(iii) porphyrins have a square planar geometry and an extra positive charge, compatible with stronger electrostatic and π-stacking interactions.
Achieving a high-performance Prussian blue analogue cathode with an ultra-stable redox reaction for ammonium ion storage
Authors: Li Chunyang , Yan Wenqi , Liang Shishuo , Wang Peng , Wang Jing , Fu Lijun , Zhu Yusong , Chen Yuhui , Wu Yuping , Huang Wei
Published: March 2019

Our synthesized ball-cutting Na-FeHCF nanocubes by controlling the stirring speed as a cathode material for ammonium ion storage exhibit high capacity, excellent rate capability, and unparalleled cycling stability.
Molecular design principles towards exo-exclusive Diels–Alder reactions
Authors: Huang Ci-Jhang , Li Elise Y.
Published: March 2019

Exo-exclusive stereoselectivity for simple, terminal-substituted dienes and dienophiles may be achieved under thermal conditions through a delicate control of substituent identities.
Ligand discrimination between active and inactive activation loop conformations of Aurora-A kinase is unmodified by phosphorylation
Authors: Gilburt James A. H. , Girvan Paul , Blagg Julian , Ying Liming , Dodson Charlotte A.
Published: March 2019

Activation loop phosphorylation changes the position of equilibrium between DFG-in-like and DFG-out-like conformations but not the conformational preference of inhibitors.
A comprehensive review of electrospinning block copolymers
Authors: Chen Lei , Wang Shuo , Yu Qianqian , Topham Paul D. , Chen Changzhong , Wang Linge
Published: March 2019

A comprehensive review on electrospinning block copolymers.
Microfluidic probing of the complex interfacial rheology of multilayer capsules
Authors: Trégouët Corentin , Salez Thomas , Monteux Cécile , Reyssat Mathilde
Published: March 2019

Microfluidics is used to produce model polymer capsules and study in situ their behavior in controlled divergent flows. Our model capsules are obtained by assembling polymer monolayers and hydrogen-bonded bilayers at the surface of oil droplets in water. We probe in situ the mechanical properties of the membranes in a controlled divergent flow generated by introducing the capsules through a constriction and then in a larger chamber.
A high performance SnO2/C nanocomposite cathode for aluminum-ion batteries
Authors: Lu Hongyan , Wan Yuanxin , Wang Tianyi , Jin Rong , Ding Peitao , Wang Rong , Wang Yong , Teng Chao , Li Linling , Wang Xiaoliang , Zhou Dongshan , Xue Gi
Published: March 2019

A novel SnO2/C AIB with high discharge capacity and long cycle life is achieved.
P2-type Na2/3Ni1/3Mn2/3O2 as a cathode material with high-rate and long-life for sodium ion storage
Authors: Liu Qiannan , Hu Zhe , Chen Mingzhe , Zou Chao , Jin Huile , Wang Shun , Gu Qinfen , Chou Shulei
Published: March 2019

The electrochemical performance of layered P2-type Na2/3Ni1/3Mn2/3O2 is highly related to the cut-off voltage and the electrolyte used.
Melamine-promoted formation of bright and stable DNA–silver nanoclusters and their antimicrobial properties
Authors: Eun Hyunmin , Kwon Woo Young , Kalimuthu Kalishwaralal , Kim Yonghwan , Lee Miran , Ahn Jung-Oh , Lee Hongweon , Lee Sang Hyun , Kim Hyung Joo , Park Hyun Gyu , Park Ki Soo
Published: March 2019

By utilizing melamine as an external stimulus, bright and stable DNA-templated silver nanoclusters are synthesized, and their superior antimicrobial properties are also demonstrated.
Correction: In situ synthesis of a silicon flake/nitrogen-doped graphene-like carbon composite from organoclay for high-performance lithium-ion battery anodes
Authors: Chen Qingze , Zhu Runliang , He Qiuzhi , Liu Shaohong , Wu Dingcai , Fu Haoyang , Du Jing , Zhu Jianxi , He Hongping
Published: March 2019

Correction for ‘In situ synthesis of a silicon flake/nitrogen-doped graphene-like carbon composite from organoclay for high-performance lithium-ion battery anodes’ by Qingze Chen et al., Chem. Commun., 2019, 55, 2644–2647.
Rhodium(i) complexes with carborane-substituted P,N ligands: investigations of electronic structure and dynamic behaviour
Authors: Coburger Peter , Kahraman Gizem , Straube Axel , Hey-Hawkins Evamarie
Published: March 2019

Two distorted square-planar RhI complexes (1 and 2) were obtained from [{RhCl(η4-cod)}2] and the respective P,N ligands.
Bio-inspired nanozyme: a hydratase mimic in a zeolitic imidazolate framework
Authors: Chen Jinxing , Huang Liang , Wang Qingqing , Wu Weiwei , Zhang He , Fang Youxing , Dong Shaojun
Published: March 2019

ZIF-8 possesses intrinsic CA-like activity and exhibits promiscuous esterase and acetylcholinesterase activities. The enzymatic activities of ZIF-8 are attributed to the bionic constituent units.
Identification of MsrA homologues for the preparation of (R)-sulfoxides at high substrate concentrations
Authors: Yang Jiawei , Wen Yuanmei , Peng Liaotian , Chen Yu , Cheng Xiaoling , Chen Yongzheng
Published: March 2019

An MsrA homologue with extremely high substrate tolerance and a wide substrate scope for the biocatalytic preparation of enantiopure sulfoxides.
Designing chain-like nickel pyro-vanadate porous spheres as an advanced electrode material for supercapacitors
Authors: Chandra Sekhar S. , Nagaraju Goli , Ramulu Bhimanaboina , Narsimulu D. , Yu Jae Su
Published: March 2019

Porous Ni2V2O7 microsphere-chains were facilely prepared in a one-pot hydrothermal technique with the aid of propanetriol.
Highly-efficient heterojunction solar cells based on two-dimensional tellurene and transition metal dichalcogenides
Authors: Wu Kai , Ma Huanhuan , Gao Yunzhi , Hu Wei , Yang Jinlong
Published: March 2019

Tellurene and TMDs show desirable type II band alignment for constructing highly-efficient heterojunction solar cells with strong charge separation and enhanced sunlight absorption.
Fast electrochemical kinetics and strong polysulfide adsorption by a highly oriented MoS2 nanosheet@N-doped carbon interlayer for lithium–sulfur batteries
Authors: Wu Jingyi , Li Xiongwei , Zeng Hongxia , Xue Yang , Chen Fangyan , Xue Zhigang , Ye Yunsheng , Xie Xiaolin
Published: March 2019

Integrating polysulfide catalyst MoS2 nanosheets and conductive N-doped carbon in a core–shell design as an interlayer for lithium–sulfur batteries.
A novel shape-stabilization strategy for phase change thermal energy storage
Authors: Liu Changhui , Xu Ze , Song Yan , Lv Peizhao , Zhao Jiateng , Liu Chenzhen , Huo Yutao , Xu Ben , Zhu Chunyu , Rao Zhonghao
Published: March 2019

A novel Lewis acid catalysis induced in situ phase change material (PCM) shape-stabilization strategy was developed to fabricate hyper-crosslinked polystyrene (HCPS) encapsulated PCMs towards highly efficient thermal energy storage.
Recent advances in synthetic methods and applications of Ag2S-based heterostructure photocatalysts
Authors: Xue Jing , Liu Jixian , Liu Yuanmeng , Li Hailong , Wang Yao , Sun Dong , Wang Wei , Huang Linjun , Tang Jianguo
Published: March 2019

Sunlight driven Ag2S-based heterostructures: promising photocatalysts for dealing with environmental and energy issues.
High-efficiency blue–green electroluminescence from sublimable cationic iridium(iii) complexes with a pyrazole-type ligand
Authors: Zhang Chen , Ma Dongxin , Liu Ruihuan , Duan Lian
Published: March 2019

High-performance blue and green luminescence is achieved using novel sublimable cationic iridium(iii) complexes with ppz as the major cyclometalated ligands.
More on algebraic properties of the discrete Fourier transform raising and lowering operators
Authors: Atakishiyeva Mesuma K. , Atakishiyev Natig M. , Loreto-Hernández Juan
Published: March 2019

In the present work, we discuss some additional findings concerning algebraic properties of the N-dimensional discrete Fourier transform (DFT) raising and lowering difference operators, recently introduced in [Atakishiyeva MK, Atakishiyev NM (2015), J Phys: Conf Ser 597, 012012; Atakishiyeva MK, Atakishiyev NM (2016), Adv Dyn Syst Appl 11, 81–92]. In particular, we argue that the most authentic symmetrical form of discretization of the integral Fourier transform may be constructed as the discrete Fourier transforms based on the odd points N only, while in the discrete Fourier transforms on the even points N this symmetry is spontaneously broken. This heretofore undetected distinction between odd and even dimensions is shown to be intimately related with the newly revealed algebraic properties of the above-mentioned DFT raising and lowering difference operators and, of course, is very consistent with the well-known formula for the multiplicities of the eigenvalues, associated with the N-dimensional DFT. In addition, we propose a general approach to deriving the eigenvectors of the discrete number operators N(N), that avoids the above-mentioned pitfalls in the structure of each even-dimensional case N = 2L.
Asymmetric α-Amination Reaction of Alkenoate Cyclic Esters Catalyzed by Chiral Tin Alkoxides
Authors: Yanagisawa Akira , Yamashita Yoshiki , Uchiyama Chika , Nakano Ryuta , Horiguchi Moe , Ida Kazuki
Published: March 2019

A catalytic enantioselective α-amination reaction of alkenoate cyclic esters with dialkyl azodicarboxylates was achieved by using a 3,3′-di(1-naphthyl)-substituted (R)-BINOL–dibromostannane complex as a chiral precatalyst in the presence of a sodium alkoxide and an alcohol. Optically active α-hydrazino ketones were obtained in moderate to high yields and with up to 91% ee in the presence of the chiral tin alkoxide generated in situ.
Multi-objective operation optimization of active distribution network based on three-terminal flexible multi-state switch
Authors: Zhang Guorong , Wang Yunqin , Peng Bo , Lu Yi , Qiu Peng , Xu Feng , Wang Chaoliang
Published: March 2019

To operate the distribution network properly is a great challenge when numerous intermittent distributed generators are involved. A novel approach for solving this issue is proposed in this paper, which is based on the three-terminal flexible multi-state switch. The three-terminal flexible multi-state switches, which are controllable, are adopted to replace the traditional tie switch and to increase the flexibility of distribution network operation and control. The timing characteristics of distribution network operation are considered, and the controllable load and the three-port flexible multi-state switch are introduced into this methodology. A multi-objective operation optimization model for an active distribution network is developed, i.e., the objective functions are designed to minimize the operating cost of the distribution network and to minimize the voltage deviation in multiple periods with consideration of demand response according to the characteristics of the active distribution network. The effectiveness of the proposed method is validated based on the IEEE 33-node test feeder by the combined Particle Swarm Optimization algorithm. The results show that the coordinated optimization of the flexible multi-state switch and the demand response improve the distribution network voltage levels significantly, which will not only bring the economic efficiency but also improve the safety and reliability of the system.
Two-dimensional turbulence dispersion in a closed domain: Influence of confinement and geometry
Authors: Flores Ramírez L. M. , Zavala Sansón L.
Published: March 2019

The spreading of passive particles immersed in a two-dimensional turbulent flow confined within a closed domain is studied analytically and numerically. The primary goal is to investigate the effect of the confinement and the geometry of the container on one and two-particle Lagrangian statistics (absolute dispersion from point sources and relative dispersion of pairs of particles, respectively). The influence of the flow confinement is analysed by performing numerical experiments with numerous particles in square boxes with different sizes. The results examine the modification of the time-dependent, dispersion curves as the particles spread out (in comparison to the turbulent regimes for unbounded flows). At long times, such curves asymptotically reach a constant value of saturation as the particles fill the container. Theoretical saturation values are calculated, and the obtained formulae are tested with the numerical results. To study the influence of the domain shape, saturation values are computed analytically for different geometries (rectangles, triangles, and ellipses). To our knowledge, the obtained expressions are new. The saturation values depend on the characteristic lengths of the domain for both regular and irregular shapes. Ranges of saturated values for the different geometries are provided. The results are compared with well-known asymptotic values for unbounded flows, thus determining the influence of the closed boundaries on particle dispersion.
Optimization of operating domain for generator set in series hybrid electric bus with power follower control strategy
Authors: Li Zhongyan , Hu Leli , Hu Donghai
Published: March 2019

Series hybrid electric buses with power follower control strategy require rotational speed of engine to operate over a wide range which may cause severe torsional vibration of generator set. In order to optimize operating domain of generator set for series hybrid electric bus, nonlinear dynamic model of generator set is established considering electromagnetic torque fluctuations. Then operating domain of generator set is optimized. Experimental results show that range of optimized rotational speed is 1500 < n < 5730, the range of optimized electromagnetic torque is 350 < T < 530.
The Moyjil site, south-west Victoria, Australia: stratigraphic and geomorphic context
Authors: Carey Stephen P. , Sherwood John E. , Kay Megan , McNiven Ian J. , Bowler James M.
Published: March 2019

Shelly deposits at Moyjil (Point Ritchie, Warrnambool), Victoria, together with ages determined from a variety of techniques, have long excited interest in the possibility of a preserved early human influence in far south-eastern Australia. This paper presents a detailed analysis of the stratigraphy of the host Bridgewater Formation (Pleistocene) at Moyjil and provides the context to the shelly deposits, evidence of fire and geochronological sampling. We have identified five superposed calcarenite–palaeosol units in the Bridgewater Formation, together with two prominent erosional surfaces that may have hosted intensive human activity. Part of the sequence is overlain by the Tower Hill Tuff, previously dated as 35 ka. Coastal marine erosion during the Last Interglacial highstand created a horizontal surface on which deposits of stones and shells subsequently accumulated. Parts of the erosional surface and some of the stones are blackened, perhaps by fire. The main shell deposit was formed by probable mass flow, and additional shelly remains are dispersed in the calcareous sand that buried the surface.
The Moyjil site, south-west Victoria, Australia: chronology
Authors: Sherwood John E. , Bowler Jim M. , Carey Stephen P. , Hellstrom John , McNiven Ian J. , Murray-Wallace Colin V. , Prescott John R. , Questiaux Daniele G. , Spooner Nigel A. , Williams Frances M. , Woodhead Jon D.
Published: March 2019

An unusual shell deposit at Moyjil (Point Ritchie), Warrnambool, in western Victoria, has previously been dated at 67±10 ka and has features suggesting a human origin. If human, the site would be one of Australia’s oldest, justifying a redetermination of age using amino acid racemisation (AAR) dating of Lunella undulata (syn. Turbo undulatus) opercula (the dominant shellfish present) and optically stimulated luminescence (OSL) of the host calcarenite. AAR dating of the shell bed and four Last Interglacial (LIG) beach deposits at Moyjil and Goose Lagoon, 30 km to the west, confirmed a LIG age. OSL analysis of the host sand revealed a complex mixing history, with a significant fraction (47%) of grains giving an early LIG age (120–125 ka) using a three-component mixing model. Shell deposition following the LIG sea-level maximum at 120–125 ka is consistent with stratigraphic evidence. A sand layer immediately below the shell deposit gave an age of ~240 ka (i.e. MIS 7) and appears to have been a source of older sand incorporated into the shell deposit. Younger ages (~60–80 ka) are due to bioturbation before calcrete finally sealed the deposit. Uranium/thorium methods were not applicable to L. undulata opercula or an otolith of the fish Argyrosomus hololepidotus because they failed to act as closed systems. A U–Th age of 103 ka for a calcrete sheet within the 240 ka sand indicates a later period of carbonate deposition. Calcium carbonate dripstone from a LIG wave-cut notch gave a U–Th age of 11–14 ka suggesting sediment cover created a cave-like environment at the notch at this time. The three dating techniques have collectively built a chronology spanning the periods before and after deposition of the shell bed, which occurred just after the LIG sea-level maximum (120–125 ka).
Analysis of the uncertainty of fuel model parameters in wildland fire modelling of a boreal forest in north-east China
Authors: Cai Longyan , He Hong S. , Liang Yu , Wu Zhiwei , Huang Chao
Published: March 2019

Fire propagation is inevitably affected by fuel-model parameters during wildfire simulations and the uncertainty of the fuel-model parameters makes forecasting accurate fire behaviour very difficult. In this study, three different methods (Morris screening, first-order analysis and the Monte Carlo method) were used to analyse the uncertainty of fuel-model parameters with FARSITE model. The results of the uncertainty analysis showed that only a few fuel-model parameters markedly influenced the uncertainty of the model outputs, and many of the fuel-model parameters had little or no effect. The fire-spread rate is the driving force behind the uncertainty of other fire behaviours. Thus, the highly uncertain fuel-model parameters associated with spread rate should be used cautiously in wildfire simulations. Monte Carlo results indicated that the relationship between model input and output was non-linear and neglecting fuel-model parameter uncertainty of the model would magnify fire behaviours. Additionally, fuel-model parameters have high input uncertainty. Therefore, fuel-model parameters must be calibrated against actual fires. The highly uncertain fuel-model parameters with high spatial-temporal variability consisted of fuel-bed depth, live-shrub loading and 1-h time-lag loading are preferentially chosen as parameters to calibrate several wildfires.
Wildfires decrease the local-scale ecosystem spatial variability of Pinus canariensis forests during the first two decades post fire
Authors: Durán Jorge , Rodríguez Alexandra , Méndez Javier , Morales Gustavo , Fernández-Palacios José María , Gallardo Antonio
Published: March 2019

The spatial variability (i.e. heterogeneity) of environmental variables determines a wide range of ecosystem features and plays a key role in regulating key ecosystem services. Wildfires are among the most significant natural disturbances that forests face, but our knowledge about their effect on ecosystem spatial variability is still limited. We used a 19-year fire chronosequence of natural, unmanaged Pinus canariensis C. Sm. ex DC forests to investigate how wildfires affect overall ecosystem spatial variability, as well as that of key faunal, plant and soil ecosystem attributes. The spatial variability of most soil variables and of the overall ecosystem tended to decrease after the fire and remain lower than the unburned plots even after 19 years. The spatial variability of plant-related variables, except for litter decomposition, as well as that of soil arthropods abundance, decreased more gradually than that of soil variables, reaching the lowest values in the plots burned 19 years before the survey. Our study provides evidence that wildfires are capable of significantly decreasing local-scale forest spatial heterogeneity through changes in the spatial variability of their different components, with likely yet unknown consequences for ecosystem functioning.
Causation and Reasoning Constructions
Authors: Kanetani Masaru
Published: March 2019

Causation and reasoning are different but related types of relationships. Both causal relations and reasoning processes may be expressed with one and the same connective word in some languages: English speakers use because and Japanese speakers use kara. How then are causation and reasoning processes related to and different from each other? How do we construe and encode them? How is because different from other conjunctions with similar meanings?
To account for these and related empirical questions, this book presents an integrated analysis in accordance with the original principles of Construction Grammar. In particular, the book shows that the analysis proposed is compatible with our general knowledge about causation and reasoning and that it is valid for English and Japanese. The proposed analysis is also comprehensively applicable to a variety of related phenomena, ranging from the just because X doesn’t mean Y construction to the innovative and less known because X construction.
Discourse strategies of mitigation in an oral corpus of narratives of life experience collected in interviews
Authors: de Almeida Carla Aurélia
Published: March 2019

Taking as reference an oral corpus in European Portuguese constituted by twenty-three narratives of life experience gathered under the frame of a sociological research project developed in the North of Portugal, this chapter analyses the strategic use of linguistic mitigation devices in the interviewer’s actions and in the interviewees’ answers followed by justifications. Narratives occurring in research interviews are part of a testimonial discourse. In the development of the topics that concern interviewees’ lifestyles and housing conditions, we can identify the occurrence of sequences of justification with the use of a “membership categorization device” that speakers use to construct identities in talk and to invoke common places to deal with dilemmas brought by the questions that occur during the interview.

This chapter seeks to demonstrate that the narratives of life experiences are the result of collaborative work in jointly constructing the sense given by the interviewer and the interviewee. As such, the analysis of discourse segments that show the “conversational involvement” (Goffman 1981; Gumperz 1982) of participants in the research interviews has contributed to the debate on the specific discourse practices taking place within these interactional research contexts in the Social Sciences.
The conditionality principle in high-dimensional regression
Authors: Azriel D
Published: March 2019

Consider a high-dimensional linear regression problem, where the number of covariates is larger than the number of observations and the interest is in estimating the conditional variance of the response variable given the covariates. A conditional and an unconditional framework are considered, where conditioning is with respect to the covariates, which are ancillary to the parameter of interest. In recent papers, a consistent estimator was developed in the unconditional framework when the marginal distribution of the covariates is normal with known mean and variance. In the present work, a certain Bayesian hypothesis test is formulated under the conditional framework, and it is shown that the Bayes risk is a constant. This implies that no consistent estimator exists in the conditional framework. However, when the marginal distribution of the covariates is normal, the conditional error of the above consistent estimator converges to zero, with probability converging to one. It follows that even in the conditional setting, information about the marginal distribution of an ancillary statistic may have a significant impact on statistical inference. The practical implication in the context of high-dimensional regression models is that additional observations where only the covariates are given are potentially very useful and should not be ignored. This finding is most relevant to semi-supervised learning problems where covariate information is easy to obtain.
Dynamic mitral valve geometry in patients with primary and secondary mitral regurgitation: implications for mitral valve repair†
Authors: Noack Thilo , Janietz Marie , Lurz Philipp , Kiefer Philipp , Sieg Franz , Marin-Cuartas Mateo , Spampinato Ricardo , Besler Christian , Rommel Karl-Philipp , Holzhey David , Mohr Friedrich-Wilhelm , Ender Joerg , Borger Michael Andrew , Seeburger Joerg
Published: March 2019

OBJECTIVES

The goal of this study was to quantify the mitral valve (MV) annulus, the MV shape and the anatomical MV orifice area throughout the cardiac cycle using 4-dimensional MV analysis software in patients with primary mitral regurgitation (PMR) and secondary mitral regurgitation (SMR) in comparison to a healthy control group.

METHODS

Three-dimensional transoesophageal echocardiograms of the MV were acquired for 29 patients with PMR, for 28 patients with SMR and for 18 healthy control subjects. The MV was quantified with regards to anterior-posterior and lateromedial diameter, annular area and circumference, intertrigonal (IT) distance, annular sphericity index, annular height to commissural width ration, and anatomical MV orifice area throughout the cardiac cycle using 3-dimensional transoesophageal echocardiography-based 4-dimensional MV advanced analysis software.

RESULTS

Normal annulus dynamics display a systolic enlargement followed by an early-diastolic plateau phase and a late-diastolic contraction. The IT distance showed a linear association with the anterior-posterior diameter (= 1.11 × IT distance) and lateromedial diameter (= 1.44 × IT distance) in the control subjects. Mitral regurgitation is associated with a less dynamic, planar and dilated annulus with small variations between PMR and SMR. The IT distance was less affected by mitral regurgitation compared to the control subjects.

CONCLUSIONS

The novel 4-dimensional MV analysis allows new insights into the dynamic MV geometry in patients with PMR and SMR compared to the control subjects. The IT distance may be used to predict annuloplasty ring sizing.
From ‘OPAT’ to ‘COpAT’: implications of the OVIVA study for ambulatory management of bone and joint infection
Authors: Seaton R A , Ritchie N D , Robb F , Stewart L , White B , Vallance C
Published: March 2019

Bone and joint infection contributes significantly to clinical activity within outpatient parenteral antimicrobial therapy (OPAT) services. The OVIVA (oral versus intravenous antibiotics for bone and joint infection) randomized study has challenged the practice of prolonged intravenous therapy, because non-inferiority of oral antibiotic therapy was demonstrated, thereby implying that early transition to oral therapy is an appropriate alternative to prolonged intravenous therapy. We examine the caveats to the study and discuss the implications for OPAT practice, highlighting the importance of careful oral antibiotic selection with attention to bioavailability, bone penetration, drug interactions, compliance and toxicity monitoring. We emphasize that ambulatory antibiotic therapy (whether intravenous or oral) in this patient group requires expert multidisciplinary management, monitoring and follow-up, and ideally should be undertaken within existing OPAT or, more accurately, complex outpatient antibiotic therapy (COpAT) services.
Increased Oxidized High-Density Lipoprotein/High-Density Lipoprotein–Cholesterol Ratio as a Potential Indicator of Disturbed Metabolic Health in Overweight and Obese Individuals
Authors: Janac Jelena M , Zeljkovic Aleksandra , Jelic-Ivanovic Zorana D , Dimitrijevic-Sreckovic Vesna S , Vekic Jelena , Miljkovic Milica M , Stefanovic Aleksandra , Kotur-Stevuljevic Jelena M , Ivanisevic Jasmina M , Spasojevic-Kalimanovska Vesna V
Published: March 2019

Background

We evaluated the qualitative characteristics of high-density lipoprotein (HDL) particles in metabolically healthy and unhealthy overweight and obese subjects.

Methods

The study involved 115 subject individuals classified as metabolically healthy and unhealthy, as in overweight and obese groups. Commercial enzyme-linked immunosorbent assay (ELISA) kits were used to measure oxidized HDL (OxHDL) and serum amyloid A (SAA) concentrations. Lipoprotein subfractions were separated using nondenaturing gradient gel electrophoresis.

Results

An independent association was shown between increased OxHDL/HDL-cholesterol ratio and the occurrence of metabolically unhealthy phenotype in the overweight and obese groups. The OxHDL/HDL-cholesterol ratio showed excellent and acceptable diagnostic accuracy in determination of metabolic health phenotypes (overweight group, AUC = 0.881; obese group, AUC = 0.765). Accumulation of smaller HDL particles in metabolically unhealthy subjects was verified by lipoprotein subfraction analysis. SAA concentrations did not differ significantly between phenotypes.

Conclusions

Increased OxHDL/HDL-cholesterol ratio may be a potential indicator of disturbed metabolic health in overweight and obese individuals.
Ribosome Provisioning Activates a Bistable Switch Coupled to Fast Exit from Stationary Phase
Authors: Remigi Philippe , Ferguson Gayle C , McConnell Ellen , De Monte Silvia , Rogers David W , Rainey Paul B
Published: March 2019

Observations of bacteria at the single-cell level have revealed many instances of phenotypic heterogeneity within otherwise clonal populations, but the selective causes, molecular bases, and broader ecological relevance remain poorly understood. In an earlier experiment in which the bacterium Pseudomonas fluorescens SBW25 was propagated under a selective regime that mimicked the host immune response, a genotype evolved that stochastically switched between capsulation states. The genetic cause was a mutation in carB that decreased the pyrimidine pool (and growth rate), lowering the activation threshold of a preexisting but hitherto unrecognized phenotypic switch. Genetic components surrounding bifurcation of UTP flux toward DNA/RNA or UDP-glucose (a precursor of colanic acid forming the capsules) were implicated as key components. Extending these molecular analyses—and based on a combination of genetics, transcriptomics, biochemistry, and mathematical modeling—we show that pyrimidine limitation triggers an increase in ribosome biosynthesis and that switching is caused by competition between ribosomes and CsrA/RsmA proteins for the mRNA transcript of a positively autoregulated activator of colanic acid biosynthesis. We additionally show that in the ancestral bacterium the switch is part of a program that determines stochastic entry into a semiquiescent capsulated state, ensures that such cells are provisioned with excess ribosomes, and enables provisioned cells to exit rapidly from stationary phase under permissive conditions.
Image Guidance for Ventricular Shunt Surgery: An Analysis of Hospital Charges
Authors: Ajmera Sonia , Motiwala Mustafa , Khan Nickalus R , Smith Lydia J , Giles Kim , Vaughn Brandy , Klimo Paul
Published: March 2019

BACKGROUND

Image guidance for shunt surgery results in more accurate proximal catheter placement. However, reduction in shunt failure remains unclear in the literature. There have been no prior studies evaluating the cost effectiveness of neuronavigation for shunt surgery.

OBJECTIVE

To perform a cost analysis using available hospital charges of hypothetical shunt surgery performed with/without electromagnetic neuronavigation (EMN).

METHODS

Hospital charges were collected for physician fees, radiology, operating room (OR) time and supplies, postanesthesia care unit, hospitalization days, laboratory, and medications. Index shunt surgery charges (de novo or revision) were totaled and the difference calculated. This difference was compared with hospital charges for shunt revision surgery performed under 2 clinical scenarios: (1) same hospital stay as the index surgery; and (2) readmission through the emergency department.

RESULTS

Costs for freehand de novo and revision shunt surgery were $23 946.22 and $23 359.22, respectively. For stealth-guided de novo and revision surgery, the costs were $33 646.94 and $33 059.94, a difference of $9700.72. The largest charge increase was due to additional OR time (34 min; $4794), followed by disposable EMN equipment ($2672). Total effective charges to revise the shunt for scenarios 1 and 2 were $34 622.94 and $35 934.94, respectively. The cost ratios between the total revision charges for both scenarios and the difference in freehand vs EMN-assisted shunt surgery ($9700.72) were 3.57 and 3.70, respectively.

CONCLUSION

From an economic standpoint and within the limitations of our models, the number needed to prevent must be 4 or less for the use of neuronavigation to be considered cost effective.
Oil Adjuvants Enhance the Efficacy of Pyraclostrobin in Managing Cucumber Powdery Mildew (Podosphaera xanthii) by Modifying the Affinity of Fungicide Droplets on Diseased Leaves
Authors: He Lifei , Li Xiaoxu , Gao Yangyang , Li Beixing , Mu Wei , Liu Feng
Published: March 2019

Adding adjuvants improved the affinity of fungicide droplets to cucumber leaves infected with powdery mildew (Podosphaera xanthii) and subsequent efficacy of fungicide treatments in reducing the disease. The affinity of oil adjuvants was quantified by adhesional tension and “work of adhesion”. Oil adjuvant-fungicide mixtures were applied to plants in field experiments to evaluate their effectiveness in disease prevention. Both the adhesional tension and work of adhesion of the adjuvants at selected concentrations increased on powdery-mildew-infected cucumber leaves more than on healthy cucumber leaves. The adjuvant GY-Tmax (GYT) displayed the best surface activity or “surfactivity” in enhancing the affinity and adherence of droplets to powdery-mildew-infected cucumber leaves, while epoxidized soybean oil (ESO), methyl oleate, and biodiesel exhibited much lower effects in terms of the surface tension, contact angle, adhesional tension, and work of adhesion. Field experiments determined that the combination of GYT at 1,000 mg liter−1 and pyraclostrobin (150 g a.i. ha−1) was most effective (91.52%) in controlling cucumber powdery mildew. Pyraclostrobin with ESO was also highly effective (ranging from 77.54 to 89.65%). The addition of oil adjuvants, especially GYT and ESO, to fungicide applications can be an effective strategy to enhance the efficacy of pesticides in controlling plant diseases by modifying the affinity of fungicide droplets to symptomatic leaves.
A review on computational modelling of phase-transition problems
Authors: Gomez Hector , Bures Miguel , Moure Adrian
Published: March 2019

Phase-transition problems are ubiquitous in science and engineering. They have been widely studied via theory, experiments and computations. This paper reviews the main challenges associated with computational modelling of phase-transition problems, addressing both model development and numerical discretization of the resulting equations. We focus on classical phase-transition problems, including liquid–solid, gas–liquid and solid–solid transformations. Our review has a strong emphasis on the treatment of interfacial phenomena and the phase-field method.

This article is part of the theme issue ‘Heterogeneous materials: metastable and non-ergodic internal structures’.
Thermal dependence of large-scale freckle defect formation
Authors: Kao A. , Shevchenko N. , Alexandrakis M. , Krastins I. , Eckert S. , Pericleous K.
Published: March 2019

The fundamental mechanisms governing macroscopic freckle defect formation during directional solidification are studied experimentally in a Hele–Shaw cell for a low-melting point Ga-25 wt.% In alloy and modelled numerically in three dimensions using a microscopic parallelized Cellular Automata Lattice Boltzmann Method. The size and distribution of freckles (long solute channels, or chimneys) are shown to be strongly dependent on the thermal profile of the casting, with flat, concave and convex isotherms being considered. For the flat isotherm case, no large-scale freckles form, while for concave or convex isotherms, large freckles appear but in different locations. The freckle formation mechanism is as expected buoyancy-driven, but the chimney stability, its long-term endurance and its location are shown to depend critically on the detailed convective transport through the inter-dendritic region. Flow is generated by curved isopleths of solute concentration. As solute density is different from that of the bulk fluid, gravity causes ‘uphill’ or ‘downhill’ lateral flow from the sample centre to the edges through the mush, feeding the freckle. An excellent agreement is obtained between the numerical model and real-time X-ray observations of a solidifying sample under strictly controlled temperature conditions.

This article is part of the theme issue ‘Heterogeneous materials: metastable and non-ergodic internal structures’.
On the theory of the unsteady-state growth of spherical crystals in metastable liquids
Authors: Alexandrov Dmitri V. , Alexandrova Irina V.
Published: March 2019

Motivated by a large number of applications, we consider the process of non-stationary growth of spherical crystals in a supercooled binary melt. The moving-boundary problem describing the unsteady-state distributions of temperature and impurity concentration around the growing crystal as well as the dynamics of its radius and growth rate is solved by means of the methods of small-parameter expansion and Laplace–Carson integral transform. We show that the growth rate of crystals contains the main contribution (which is proportional to the supercooling degree Δ) and the first correction (which is proportional to Δ
2
t
, where
t
is time). The second correction is also found. The non-stationary temperature and concentration fields are determined as power functions of Δ and
t
. We demonstrate that the first corrections to the dynamics of crystal radius
R
(
t
) and its growth rate
V
(
t
) play an important role. It is shown that
R
(
t
) and
V
(
t
) can change more than twice in comparison with the previously known steady-state solution with the course of time. Such a behaviour will significantly modify the dynamics of a polydisperse ensemble of crystals evolving in a metastable liquid.

This article is part of the theme issue ‘Heterogeneous materials: metastable and non-ergodic internal structures’.
Mouth Function Determines The Shape Oscillation Pattern In RegeneratingHydraTissue Spheres
Authors: Wang R. , Goel T. , Khazoyan K. , Sabry Z. , Quan H.J. , Diamond P.H. , Collins E.M.S.
Published: March 2019

Hydrais a small freshwater polyp capable of regeneration from small tissue pieces and from aggregates of cells. During regeneration, a hollow bilayered sphere is formed that undergoes osmotically driven shape oscillations of inflation and rupture. These oscillations are necessary for successful regeneration. Eventually, the oscillating sphere breaks rotational symmetry along the future head-foot axis of the animal. Notably, the shape oscillations show an abrupt shift from large amplitude, long period oscillations to small amplitude, short period oscillations. It has been widely accepted that this shift in oscillation pattern is linked to symmetry breaking and axis formation. However, recent work showed that regenerating tissue pieces inherit the parent animal’s body axis and thus are asymmetric from the beginning. Thus, there is no mechanistic explanation for the observed shift in oscillation pattern and no clear understanding of its significance forHydraregeneration. Usingin vivomanipulation and imaging, we quantified the shape oscillation dynamics and dissected the timing and triggers of the pattern shift. Our experiments demonstrate that the shift in the shape oscillation pattern in regeneratingHydratissue pieces is caused by the formation of a functional mouth, thereby linking morphological readouts to physiologically relevant events during regeneration. This study shows the power of using modern experimental techniques to revisit old questions in pattern formation and development.
The Marginal Cells of theCaenorhabditis elegansPharynx Scavenge Cholesterol and Other Hydrophobic Small Molecules
Authors: Kamal Muntasir , Moshiri Houtan , Magomedova Lilia , Han Duhyun , Nguyen Ken CQ , Yeo May , Knox Jess , Bagg Rachel , Won Amy M. , Szlapa Karolina , Yip Christopher , Cummins Carolyn L. , Hall David H. , Roy Peter J.
Published: March 2019

The nematode wormCaenorhabditis elegansis a bacterivore filter feeder. Through the contraction of the worm’s pharynx, a bacterial suspension is sucked into the pharynx’s lumen. Excess liquid is then shunted out of the buccal cavity through ancillary channels that are made from specialized pharyngeal cells called marginal cells. Through the characterization of our library of worm-bioactive small molecules (a.k.a.wactives), we found that more than one third of wactives visibly accumulate inside of the marginal cells as crystals or globular spheres. Wactives that visibly accumulate are typically more hydrophobic than those that do not. To understand why wactives accumulate specifically in marginal cells, we performed a forward genetic screen for mutants that resist the lethality associated with one crystallizing wactive. We identified a presumptive sphingomyelin-synthesis pathway that is necessary for crystal and sphere accumulation. Sphingomyelin is a phospholipid that is enriched in the outer leaflet of the plasma membranes of most metazoans. We find that the predicted terminal enzyme of this pathway, sphingomyelin synthase 5 (SMS-5), is expressed in the pharynx, contributes to sphingomyelin abundance, and that its expression in marginal cells is sufficient for wactive accumulation. We also find that the expression of SMS-5 in the marginal cells is necessary for the proper absorption of exogenous cholesterol, without whichC. eleganscannot develop. We conclude that the sphingomyelin-rich plasma membrane of the marginal cells acts as a sink to scavenge important hydrophobic nutrients from the filtered liquid that might otherwise be shunted back into the environment.

One sentence summary

The anterior pharynx ofC. elegansis a Sink for Hydrophobic Small Molecules