bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative coherent Raman scattering microscopies: new tools for the material and life sciences
Authors: Volkmer Andreas
Published: December 2016

Unlike optical microscopies that are based on fluorescence detection, Raman‐based micro‐spectroscopies provide vibrational signatures that themselves represent quantitative measures of the sample's molecular composition and structures, which for example can be successfully exploited as an intrinsic vibrational contrast of endogenous biomolecular species for label‐free tumour diagnostic imaging [1]. In particular, by exploiting the coherent driving and detection of Raman modes in coherent anti‐Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS), coherent Raman scattering (CRS) microscopy allows the point‐by‐point chemical mapping of molecular compounds, which is often difficult to attain by conventional fluorescence and incoherent vibrational microscopy techniques. Here, we will review on two CRS modalities that provide quantitative molecular information [2]: (i) high‐speed stimulated Raman loss (SRL) imaging at video‐rates and (ii) hyperspectral CARS imaging that provides access to the full wealth of chemical and physical structure information of an a priori unknown molecular sample. We will discuss their underlying principles, their state‐of‐the‐art experimental realizations, and demonstrate exemplifying applications for the label‐free and noninvasive 3D visualization of chemical composition as well as of molecular structure properties of (bio)molecular components in heterogeneous and complex materials, ranging from polymers to living cells.

Particular emphasis will be given to the combination of coherent Raman scattering spectroscopy with optical microscopy, which has emerged as a highly sensitive and chemically selective tool for the extraction of quantitative molecular structure information from purely imaginary hyperspectral data cubes of the sample's complex third‐order nonlinear susceptibility, χ
(3)
(ν,x,y,z), as obtained by fast hyperspectral CARS imaging in conjunction with spectral phase retrieval algorithms. We will introduce a novel concept based on the wavelet prism decomposition and the maximum entropy method (MEM) for the fast and robust reconstruction of the pure vibrational response of the molecular sample inside a sub‐femtoliter probe volume in the presence of experimental artefacts, which may obstruct the accurate phase retrieval from the experimental normalized CARS pixel spectra [3]. Furthermore, we will present exemplifying applications (see Fig. 1) for the quantitative 3D mapping of chemical composition in living cells, the intracellular chemical structure analysis of biologically relevant lipids, and the physical 3D structure analysis in polymers.
Split‐illumination Electron Holography Applied to Electrostatic Potential Analyses of Oxide Heterojunctions with Polar Discontinuity
Authors: Tanigaki Toshiaki , Nakamura Masao , Kagawa Fumitaka , Soon Park Hyun , Matsuda Tsuyoshi , Shindo Daisuke , Tokura Yoshinori , Kawasaki Masashi
Published: December 2016

Electron holography using interference of electron wave is one of quantitative microscopic techniques to visualize electromagnetic fields at nanometer scale. The long standing problem in this method was that the observable area was limited near the sample edge. To solve this problem, we developed split‐illumination electron holography [1]. In this method, a coherent electron wave is separated into two coherent waves (object and reference waves) using biprism placed in the illumination system. The coherence degree of these electron waves do not change when they are separated. This makes it possible to achieve high precision holographic observation of an area far from the sample edge. As one of applications, electrostatic potential analysis of oxide heterojunctions with polar discontinuity will be presented.

The discovery of the two‐dimensional interface conduction in the LaAlO
3
/SrTiO
3
(LAO/STO) heterojunction with polar discontinuity made a revival of the interest on the polar interface [2]. The emergence of high‐mobility in LAO/STO is generally explained by the polar catastrophe scenario. Although the spontaneous electric polarization due to this charge redistribution was theoretically predicted, the existence of the mobile charges made it difficult to confirm the spontaneous polarization in LAO/STO junction. We explored oxide heterojunctions where the spontaneous polarization plays a dominant role in the charge screening and selected the LaFeO
3
(LFO)/STO as target interface. Figure 1 shows two types of atomic sequences at the interfaces and reversal of electrostatic potential slopes in LFO. The results indicate that the originally non‐polar LFO are converted into polar as a consequence of the polar catastrophe [3].
Our muscle at near‐atomic resolution ‐ Cryo‐EM structure of the F‐actin‐tropomyosin complex
Authors: von der Ecken Julian , Müller Mirco , Lehman William , Manstein Dietmar J. , Penczek Pawel A. , Raunser Stefan
Published: December 2016

Muscular movement plays an essential role not only in our lives but also describes a fundamental mechanism of force production. Filamentous actin (F‐actin) is the major protein of muscle thin filaments, and actin microfilaments are the main component of the eukaryotic cytoskeleton. The interaction of myosin with actin filaments is the central feature of muscle contraction and cargo movement along actin filaments.In striated muscle fibres, this interplay is mainly regulated by tropomyosin and troponin. Although crystal structures for monomeric actin are available, the difficulty of obtaining diffracting crystals, however, has prevented structure determination by crystallography of F‐actin. High‐resolution structures of F‐actin in complex are still missing, hampering our understanding of how disease‐causing mutations affect the function of thin muscle filaments and affecting skeletal and cardiac muscles.

We solved the three‐dimensional structure of F‐actin in complex with tropomyosin at a resolution of 3.7 Å (von der Ecken et al., 2015). We used cutting edge transmission electron cryomicroscopy and direct electron detectors and implemented new methods for processing of the data. The structure reveals insights in the inner interaction of the F‐actin subunits and the interplay of F‐actin and tropomyosin at near‐atomic resolution.
Information in localisation microscopy
Authors: Cox Susan
Published: December 2016

Localisation microscopy is a powerful tool for imaging structures at a lengthscale of tens of nm, but its utility for live cell imaging is limited by the time it takes to acquire the data needed for a super‐resolution image. The acquisition time can be cut by more than two orders of magnitude by using advanced algorithms which can analyse dense data, trading off acquisition and processing time.

Modelling the entire localisation microscopy dataset using a Hidden Markov Model allows localisation information to be extracted from extremely dense datasets. This Bayesian analysis of blinking and bleaching (3B) is able to image dynamic processes in live cells at a timescale of a few seconds, though it is very computationally intensive, requiring at least several hours of analysis. We demonstrate the performance of 3B on various live cell systems, including cardiac myocytes and podosomes, showing a resolution of tens of nm with acquisition times down to a second.

While analysing higher density images can improve the speed at which the data required for a super‐resolution reconstruction is acquired, there are still limits to the speed which can be achieved. Unlike in conventional fluorescence microscopy, these limits are not just set by the properties of the microscope, but are determined by the structure of the sample itself. This is because the local sample structure affects how quickly the information necessary to create an image of a certain resolution can be transmitted through the optical system. The theoretical limits will be discussed, and the effect on live cell experiments demonstrated.
A huge but elusive macromolecular cage in enterobacterial stress response as seen by
cryoEM
and
X‐ray
crystallography
Authors: Kandiah Eaazhisai , Malet Hélène , Carriel Diego , Perard Julien , Bacia Maria , Houry Walid A , Ollagnier de Choudens Sandrine , Elsen Sylvie , Gutsche Irina
Published: December 2016

The
E. coli
inducible lysine decarboxylase LdcI is an important acid stress response enzyme, whereas the AAA+ ATPase RavA is involved in multiple stress response pathways. A complex between these two proteins is thought to counteract acid stress under starvation in
E. coli
. We solved the crystal structure of the RavA monomer and combined it with a negative stain EM reconstruction of the RavA‐ADP hexamer (El Bakkouri
et al
., 2010). We also determined the crystal structure of the LdcI double pentamer (Kanjee
et al
., 2011). While these structures provided important insights into the functions of these individual proteins, the design principles of the LdcI‐RavA complex appeared even more enigmatic because it was difficult to envision how a decamer can bind a hexamer. CryoEM analysis allowed us to fit together the pieces of the jigsaw and revealed that the LdcI‐RavA complex is a surprising macromolecular cage of the size of a ribosome formed by two LdcI decamers and five RavA hexamers (Malet
et al
., 2014). We identified molecular determinants of this interaction and specific elements essential for complex formation, as well as conformational rearrangements associated with the pH‐dependent LdcI activation and with the RavA binding (Malet
et al
., 2014; Kandiah
et al
., 2016). Moreover, we uncovered differences between the LdcI and its close paralogue, the second E. coli lysine decarboxylase LdcC thought to play mainly a biosynthetic role, finally explaining why only the acid stress response enzyme is capable of binding RavA and forming the cage. Multiple sequence alignment coupled to a phylogenetic analysis reveals that certain enterobacteria exert evolutionary pressure on the lysine decarboxylase towards the cage‐like assembly with RavA, implying that this complex may have an important function under particular stress conditions (Kandiah
et al
., 2016). Research on structure‐functional relationships of this system by a combination of cryoEM, super‐resolution fluorescence microscopy and other structural, biochemical, biophysical and cell biology techniques is on‐going.
Structure and nanomechanical properties of a wonderfully complex material, the primary cell wall of plants: recent progress based on
AFM
and
FESEM
Authors: Cosgrove Daniel , Zhang Tian , Zheng Yunzhen
Published: December 2016

Growing plant cells synthesize a strong yet extensible cell wall (=extracellular matrix) composed of long, thin cellulose microfibrils that are laterally bonded to one another in organized layers ~ 40 nm thick and that are embedded in a hydrated matrix consisting of complex polysaccharides (pectins, hemicelluloses). I will briefly review the biosynthetic origins of these wall components and what is known about their assembly to form a hierarchically‐structured hydrated material with diverse physical and chemical properties. Recent advances in atomic force microscopy (AFM), field effect scanning electron microscopy (FESEM), and solid‐state NMR have led to a rethinking of how these wall components interact with one another and how cells regulate the irreversible expansion (growth) of the cell wall
1‐4
. With AFM we have characterized the detailed organization of recently‐deposited cellulose microfibrils in never dried cell walls of onion epidermis. The interaction of microfibrils with matrix can be visualized in two‐color maps based height (which emphasizes microfibrils and modulus or adhesion, which highlight soft matrix. Additionally, when the cell walls are stretched to reveal microfibril re‐arrangements after plastic or elastic deformation or after enzyme‐mediated cell wall creep, we find different patterns of microfibril movements. FESEM images of the same material (except dried) detect only a surface layer of pectins that obscure the underlying microfibrils. These can be unveiled by enzyme digestions to selectively remove pectins. Some of the remaining unsolved problems in cell wall structure and polysaccharide interactions will be highlighted.
High resolution
STEM
imaging and analysis of
2D
crystal heterostructure devices and nanoparticle catalysts
Authors: Haigh Sarah , Slater Thomas , Rooney Aidan , Prestat Eric , Gorbachev Roman , Withers Freddie , Novoselov Konstantin , Andre Geim
Published: December 2016

The new generation of aberration corrected scanning transmission electron microscope (STEM) instruments optimized for high spatial resolution energy dispersive x‐ray (EDX) spectroscopy provide exciting opportunities for elemental analysis of nanoscale objects. Here I will discuss recent example applications from our studies of nanoparticle catalysts and 2D device heterostructures where these analytical capabilities have provided new insights to interpret the electronic and catalytic properties of such systems.

Elementally sensitive STEM EDX electron tomography provides a route to understanding full 3D morphology and chemistry with nanometre resolution. I will demonstrate results showing the effect of different elemental segregation on the catalytic performance of bimetallic nanoparticles [1]. I will also discuss the current limitations of this technique, including compensation of detector shadowing using a time varied acquisition scheme, and recent progress towards quantitative analysis [2,3].

I will also present work demonstrating that cross sectional STEM‐EDX spectrum imaging can be used to reveal the internal atomic structure of van der Waals heterostructure devices produced by layering together multiple 2D crystals [4]. Recently we have studied light emitting diode devices, produced by mechanical exfoliation and subsequent stacking of 13 different 2D crystals, including 4 MoS
2
monolayer quantum wells [5]. Using cross sectional STEM spectrum imaging we reveal that the crystal interfaces of such devices are atomically flat and provide detailed structural information to help to explain the electroluminescence results obtained. Other 2D crystal heterostructures will also be discussed including those incorporating air sensitive 2D crystals, such as black phosphorus, that require fabrication under an argon atmosphere to preserve the device performance [6].

Finally recent work where customised modification of an in situ STEM holder system [7] has allowed us to perform high spatial resolution STEM‐EDX spectrum imaging during
in‐situ
gas and liquid phase experiments and at elevated temperature [8].
New developments in direct electron detecting cameras and their importance for cryo‐
EM
Authors: Henderson Richard
Published: December 2016

Direct electron detectors have played a key role in the recent increase in the power of single particle electron cryomicroscopy (cryo‐EM). In this talk, I will summarise the background to these recent developments, give a practical guide to their optimal use, and discuss future directions.
Beating Time and Space resolutions in Ultrasound for disruptive innovations in Medical Imaging
Authors: Tanter Mickael
Published: December 2016

In the last fifteen years, the introduction of plane or diverging wave transmissions rather than line by line scanning focused beams has broken the conventional barriers of ultrasound imaging. By using such large field of view transmissions, the frame rate reaches the theoretical limit of physics dictated by the ultrasound speed and an ultrasonic map can be provided typically in tens of micro‐seconds (several thousands of frames per second). Interestingly, this leap in frame rate is not only a technological breakthrough but it permits the advent of completely new ultrasound imaging modes, including shear wave elastography, electromechanical wave imaging, ultrafast doppler, ultrafast contrast imaging, and even functional ultrasound imaging of brain activity (fUltrasound) introducing Ultrasound as an emerging full‐fledged neuroimaging modality.

At ultrafast frame rates, it becomes possible to track in real time the transient vibrations – known as shear waves – propagating through organs. Such “human body seismology” provides quantitative maps of local tissue stiffness whose added value for diagnosis has been recently demonstrated in many fields of radiology (breast, prostate and liver cancer, cardiovascular imaging, …). Today, first clinical ultrafast ultrasound scanners are available in the clinical world with such real time imaging of tissue elasticity. This is the first example of an ultrafast Ultrasound approach now widely spread in the clinical medical ultrasound community.

For blood flow imaging, ultrafast Doppler permits high‐precision characterization of complex vascular and cardiac flows. It also gives ultrasound the ability to detect very subtle blood flow in very small vessels. In the brain, such ultrasensitive Doppler paves the way for
fUltrasound
(functional ultrasound imaging) of brain activity with unprecedented spatial and temporal resolution compared to fMRI.

Combined with contrast agents, our group demonstrated that Ultrafast Ultrasound Localization could provide a first
in vivo
and non‐invasive imaging modality at microscopic scales deep into organs.

Many of these ultrafast modes should lead to major improvements in ultrasound screening, diagnosis, and therapeutic monitoring.
Properties of low‐dimensional electron‐beam‐sensitive objects by spherical and chromatic aberration‐corrected low‐voltage high‐resolution transmission electron microscopy and spectroscopy
Authors: Kaiser Ute
Published: December 2016

Spherical aberration correction has become inevitable in materials science for atomic‐resolution imaging of conventional objects by transmission electron microscopy at medium accelerating voltages (80‐300kV). However, low‐Z and radiation‐sensitive low‐dimensional objects often require lower accelerating voltages because the threshold for knock‐on damage is below 80kV for these materials. Unfortunately, the resolution of spherical aberration‐corrected transmission electron microscopy at an accelerating voltage less than 80 kV with a standard Schottky type or field‐emission electron source is strongly limited by the chromatic aberration of the objective lens. Here we report on our approach to achieve atomic resolution at voltages in the range between 20‐80kV in transmission electron microscopy [1,2,3]. We apply the newly‐developed aberration corrector that corrects for both, spherical and chromatic aberration of the objective lens. First experimental results of low‐dimensional objects will be presented.

The performance of the
SALVE
(Sub‐Angstrom Low‐Voltage Electron microscopy) microscope enables atomic‐resolution imaging and high‐resolution energy‐filtered (EF)‐TEM with large energy windows even at 20kV accelerating voltage. Obviously, no damping of the contrast transfer function by chromatic aberration has to be considered in the image calculation routine, although image spread due to thermal magnetic field noise [4] needs to be taken into account as a new source of contrast transfer damping. The envelope now results from image‐spread and residual defocus [5]. Image calculations are performed in dependence of the electron dose [6]. Figure 1 shows experimental HRTEM images of single‐layer graphene at 30kV; as the usable aperture is about 65mrad, consequently an information limit of 107pm has been achieved. The comparison of the line profiles through the calculated and experimental images of a defect in graphene demonstrates that a good match has been obtained assuming Si substitutions. Moreover, on the example of TiO
2
we demonstrate the new capabilities for EFTEM imaging. We now can use an energy window of about 20 eV where the defocus changes by only about 2 nm. This enables previously reported high‐resolution EFTEM [7] imaging but at low accelerating voltages.

In addition, we discuss the importance of sophisticated sample preparation approaches [8,9] and show results in imaging and spectroscopy on low‐dimensional objects [10‐15].
Structure of hibernating ribosomal complexes from Gram‐positive pathogenic bacteria Staphylococcus aureus, solved by single particle cryo‐EM
Authors: Khusainov Iskander , Vicens Quentin , Bochler Anthony , Myasinkov Alexander , Marzi Srefano , Romby Pascale , Yusupova Gulnara , Yusupov Marat , Hashem Yaser
Published: December 2016

Protein synthesis is a universally conserved process that is assured by a macromolecule called the ribosome (3.4 – 4.5 Mda). In spite of the conservation of the ribosome among all orders of life, its structure presents significant differences between eukaryotes and bacteria. Bacterial ribosome, smaller than its eukaryotic counterpart, presents specific particularities to which we owe the efficiency of numerous commonly used antibiotics that target the latter without hindering protein synthesis in the host. Such structural differences are found in all steps of protein translation.

Here, we attempt to explore by cryo‐electron microscopy the ribosomal hibernation, one of the most mysterious regulation processes of protein translation in bacteria. Hibernation is a vital process that can be triggered as a response to stress and aims at shutting down translation in a reversible manner so that translation can recover quickly after the alleviation of stress. Here, we show several 3D reconstructions of hibernation ribosomal complexes from the Gram‐positive pathogenic bacteria
Staphylococcus aureus
. Our structures display the formation of a disome (ribosomal dimer) mediated by a peculiar hibernation factor (HPF), thus setting up the disome in a unique fashion, different than other dimers of known bacterial species indicating the uniqueness of this process in
S. aureus
and perhaps in gram‐positive bacteria more generally. In spite of the size of the imaged asymmetric complexes (~7 Mda, ~550Å diameter), our data‐processing yielded several structures after particle sorting presenting an average resolution of ~3.7Å, thus enabling the modelling
ab initio
of
S. aureus
HPF, so far of unknown structure.

Our results represent a significant advance and pinpoint a unique process that can be targeted for designing drugs of improved specificity and efficiency against this dangerous pathogen and Gram‐positive bacteria more generally.
Environmental issues addressed by analytical
TEM
and X‐rays absorption spectroscopies
Authors: WANG Yuheng , ADRA Areej , IKOGOU Maya , ONA‐NGUEMA Georges , JUILLOT Farid , MENGUY Nicolas , MORIN Guillaume
Published: December 2016

Fe‐bearing minerals are widespread in earth surface environments, including soils, sediments and aquifers. Owing to their large specific area, these minerals can efficiently scavenge inorganic pollutants such as arsenic, nickel, etc. Metabolic activities of native microorganisms are capable of weathering either directly by enzymatic reduction, or indirectly through the reaction of biogenic hydrogen sulfides with Fe(III)‐minerals. Metals/metalloids associated with such ferric solids phases can be released into solutions or be sequestrated into biogenic Fe(II)‐containing minerals that result from direct and indirect bacterial transformation of Fe(III)‐minerals. Here we investigate, using X‐ray absorption spectroscopy (XAS) and high resolution transmission electron microscopy (HRTEM), the role (
i
) of Fe(II)‐bearing minerals such magnetite and mackinawite nanoparticles to scavenge inorganic pollutants (arsenic or nickel), and (
ii
) of aluminum‐rich ferrihydrites in arsenic scavenging in river‐bed sediments from a circumneutral river (pH 6−7) impacted by an arsenic‐rich acid mine drainage (AMD). We therefore present recent investigations of natural and model systems that illustrate the relation between the crystal chemistry of metal/metalloids and their speciation and distribution at the Earth's surface. Our findings show the importance of nanocrystalline Fe‐minerals in delaying the long‐term impact of inorganic pollutants natural environments.
Optical investigation of a novel sensory interface linking spinal fluid to motor circuits in vivo
Authors: Wyart Claire
Published: December 2016

The cerebrospinal fluid (CSF) is a complex solution circulating around the brain and spinal cord. Behavior has long been known to be influenced by the content and flow of the CSF, but the underlying mechanisms are completely unknown. CSF‐contacting neurons by their location at the interface with the CSF are in ideal position to sense CSF cues and to relay information to the nervous system. By combining electrophysiology, optogenetics, bioluminescence monitoring with calcium imaging in vivo, we demonstrate that neurons contacting the CSF in the spinal cord detect local bending and in turn feed back GABAergic inhibition to multiple interneurons driving locomotion in the ventral spinal cord. Behaviour analysis of animals deprived of this mechano‐sensory pathway reveals its contribution in modulating key parameters of locomotion. Altogether our approach developed in a transparent animal model shed light on a novel pathway enabling sensory motor integration between the CSF and motor circuits in the spinal cord.
Mechanical Properties of the Extracellular Matrix Affect Growth Plate Morphogenesis
Authors: Prein Carina , Warmbold Niklas , Farkas Zsuzsanna , Schieker Matthias , Aszodi Attila , Clausen‐Schaumann Hauke
Published: December 2016

The growth plate (GP) is a dynamic tissue driving bone elongation through chondrocyte proliferation, hypertrophy and matrix production. The extracellular matrix (ECM) is the major determinant of GP biomechanical properties and assumed to play a crucial role for chondrocyte geometry and arrangement, thereby guiding proper growth plate morphogenesis and bone elongation. To elucidate the relationship between morphology and biomechanics during cartilage morphogenesis, we have investigated structural and elastic properties of the proliferative zone of the murine GP by atomic force microscopy (AFM) from the embryonic stage to adulthood. We observed a progressive cell flattening and arrangement into columns from embryonic day 13.5 until postnatal week 2, correlating with an increasing collagen density and ECM stiffness, followed by a nearly constant cell shape, collagen density and ECM stiffness from week 2 to 4 months. At all ages, we found marked differences in the density and organization of the collagen network between the intracolumnar matrix, and the intercolumnar matrix, associated with a roughly two‐fold higher stiffness of the intracolumnar matrix compared to the intercolumnar matrix. This difference in local ECM stiffness seems therefore to force the cells to arrange in a columnar structure upon cell division and drive bone elongation during embryonic and juvenile development.
Super‐resolution technologies to probe nuclear architecture
Authors: NOLLMANN Marcelo
Published: December 2016

Chromosomes from bacteria to humans are organized at the sub‐megabase scale into genomic domains. We will present examples of how super‐resolution microscopies can be combined with new DNA labeling technologies and genome‐wide chromosome capture methods to shed light into the mechanisms of formation and regulation of genome architecture. In particular, we will present our recent advances in multifocus plane microscopy for 3D single‐molecule localization microcopy, two‐color STORM to study genome structure, and high‐thoughput 3D‐SIM‐based image analysis to investigate chromosome segregation.
Ultrafast Laser Spectroscopy of Two‐Dimensional Materials Beyond Graphene
Authors: Ceballos Frank , Zhao Hui
Published: December 2016

Starting with the discovery of graphene in 2004, the interest in two‐dimensional materials since then has been exponentially growing. Across many disciplines, their exceptional electrical, chemical, thermal, and optical properties have drawn considerable attention that has created an entire field within a decade of their discovery. Driven by the mechanical exfoliation technique that allows for the quick exploration of these two‐dimensional materials and their novel devices, joint efforts have been made in order to understand and exploit their potential, consequently leading to the development of their large‐scale growth. This review focuses on recent studies using ultrafast laser spectroscopy that have revealed the photocarrier dynamics in two‐dimensional materials and laid the foundation of their behavior. We provide a brief introduction on ultrafast laser spectroscopy, discuss several aspects of the photocarrier dynamics, and conclude with our perspective on future developments.
A Foolproof Method to Fabricate Integrated Electrodes with 3D Conductive Networks: A Case Study of MnOx@C‐Cu as Li‐Ion Battery Anode
Authors: Cao Kangzhe , Liu Huiqiao , Chang Xiaoya , Li Yang , Wang Yijing , Jiao Lifang
Published: December 2016

Integrated electrodes have attracted numerous attention for their wide applications, such as in battery, supercapacitor, and catalyst (for oxygen reduction reaction, oxygen evolution reaction, and hydrogen reduction reaction). When used for Li‐ion batteries, these electrodes always show superior electrochemical performance for their merits, such as binder free, open framework, and robust adherence. Nevertheless, the current integrated electrodes usually lack an effective conductive network or require a tedious postfabrication process. Herein, polyvinylpyrrolidone (PVP) is used as a bifunctional material, for its cohesiveness and ability of acting as N‐doping carbon precursor, to fabricate integrated electrodes with 3D conductive networks. Owing to its high N content (12.4 wt%), large volume shrinkage, and gas production, porous conductive network forms when PVP is carbonized. This strategy is foolproof, low cost, and can be scaled‐up. The electrodes fabricated by this method epitomize the merits of 3D conductive network, integrated structure, and open framework. As an example, MnOx@C‐Cu shows excellent electrochemical performance (1030 mA h g−1 at 0.4 A g−1 up to 350th cycles, and 320 mA h g−1 at 2.0 A g−1) when evaluated as Li‐ion battery anode owing to these merits. Moreover, other functional integrated electrodes are developed, paving an easy way to fabricate integrated electrodes with 3D conductive networks.
Short and Efficient Chemoenzymatic Syntheses of non‐Natural (−)‐Muscarine and (+)‐allo‐Muscarine from Cyano‐Sugar Precursors Catalyzed by Immobilized Burkholderia cepacia Lipase
Authors: Carnero Alejandro , Sanghvi Yogesh S. , Gotor Vicente , Fernández Susana , Ferrero Miguel
Published: December 2016

Enantiopure (2R)‐configured non‐natural (−)‐muscarine and (+)‐allo‐muscarine were efficiently synthesized by a chemoenzymatic approach from an easily accessible cyano‐sugar available on a large‐scale. The key enzymatic hydrolysis step was accomplished by immobilized Burkholderia cepacia lipase (also known as Pseudomonas cepacia lipase, PSL‐IM). The PSL‐IM‐mediated regioselective hydrolysis of the 5‐O‐toluoyl ester group in α‐ and β‐cyano‐sugars, furnished 3‐O‐toluoyl‐α‐cyano‐sugar and 3‐O‐toluoyl‐β‐cyano‐sugar, respectively, with total selectivity and in excellent yields. To demonstrate the industrial utility of this method, 3‐O‐toluoyl‐β‐cyano‐sugar was synthesized on a 10 g scale using PSL‐IM and the catalyst was reused. A key feature of the synthesis route described herein is the simultaneous hydrogenolysis of a tosyl group, reduction of a nitrile and deprotection of a toluoyl group using LiAlH4 in a one‐pot procedure. This study offers a green protocol for synthesis of two muscarine derivatives in high yields employing a concise four‐step strategy.

magnified image
A Copper‐Benzotriazole‐Based Coordination Polymer Catalyzes the Efficient One‐Pot Synthesis of (N′‐Substituted)‐hydrazo‐4‐aryl‐1,4‐dihydropyridines from Azines
Authors: Kallitsakis Michael , Loukopoulos Edward , Abdul‐Sada Alaa , Tizzard Graham J. , Coles Simon J. , Kostakis George E. , Lykakis Ioannis N.
Published: December 2016

A series of new (N′‐substituted)‐hydrazo‐4‐aryl‐1,4‐dihydropyridines was successfully synthesized via a facile one‐pot catalytic pathway utilizing azines and propiolate esters as starting materials and a one‐dimensional copper benzotriazole‐based coordination polymer as catalyst. In the absence of catalyst, the corresponding 5‐substituted 4,5‐dihydropyrazoles were formed in moderate to high yields. Fine‐tuning of the catalysts allowed us to gain more insights regarding the plausible reaction mechanism.

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SelectfluorTM on a PolyHIPE Material as Regenerative and Reusable Polymer‐Supported Electrophilic Fluorinating Agent
Authors: Kawada Kosuke , Okano Koji , Iskra Jernej , Krajnc Peter , Cahard Dominique
Published: December 2016

The first recyclable polymer‐supported electrophilic fluorinating agent was prepared by reaction of molecular fluorine with the triethylenediamine motif that is grafted onto a poly(4‐vinylbenzyl chloride‐co‐divinylbenzene) polyHIPE material. The resulting polymeric SelectfluorTM‐type reagent demonstrated high efficiency in the fluorination of naphthol in the course of repeated sequences of fluorination and regeneration. It also reacted with the enol form and the sodium enolate of 1,3‐dicarbonyl compounds.

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Mixed‐Valence Nickel Bis(azamacrocycle) Compounds with Ghost‐Leg‐type Sheets
Authors: Hashiguchi Ryota , Otsubo Kazuya , Maesato Mitsuhiko , Sugimoto Kunihisa , Fujiwara Akihiko , Kitagawa Hiroshi
Published: December 2016

The fabrication of so‐called ghost‐leg sheets and their electronic properties is reported. This unique sheet structure is composed of one‐dimensional mixed‐valence nickel chains, which are linked with one another by bis(azamacrocycle) ligands. They are also topologically unique NiII/NiIII mixed‐valence complexes, as confirmed by X‐ray and optical measurements. Moreover, their magnetic susceptibilities indicated two‐dimensional antiferromagnetic behavior following the Fisher 1D chain model with interchain interactions, where spins on NiIII sites mutually interact antiferromagnetically in the sheets.
Quasimolecules in Compressed Lithium
Authors: Miao Mao‐sheng , Hoffmann Roald , Botana Jorge , Naumov Ivan I. , Hemley Russell J.
Published: December 2016

Under high pressure, some materials form electrides, with valence electrons separated from all atoms and occupying interstitial regions. This is often accompanied by semiconducting or insulating behavior. The interstitial quasiatoms (ISQ) that characterize some high pressure electrides have been postulated to show some of the chemical features of atoms, including the potential of forming covalent bonds. It is argued that in the observed high‐pressure semiconducting Li phase (oC40, Aba2), an example of such quasimolecules is realized. The theoretical evaluation of electron density, electron localization function, Wannier orbitals, and bond indices forms the evidence for covalently bonded ISQ pairs in this material. The quasimolecule concept thus provides a simple chemical perspective on the unusual insulating behavior of such materials, complementing the physical picture previously presented where the global crystal symmetry of the system plays the major role.
Oxidative Intramolecular 1,2‐Amino‐Oxygenation of Alkynes under AuI/AuIII Catalysis: Discovery of a Pyridinium‐Oxazole Dyad as an Ionic Fluorophore
Authors: Shaikh Aslam C. , Ranade Dnyanesh S. , Rajamohanan Pattuparambil R. , Kulkarni Prasad P. , Patil Nitin T.
Published: December 2016

Oxidative intramolecular 1,2‐amino‐oxygenation reactions, combining gold(I)/gold(III) catalysis, is reported. The reaction provides efficient access to a structurally unique ionic pyridinium‐oxazole dyad with tunable emission wavelengths. The application of these fluorophores as potential biomarkers has been investigated.
Assessment of pre‐treatment technologies for bioethanol production from sugarcane bagasse considering economics and environmental impact
Authors: Crimes J. , Isafiade A.J. , Fraser D.M. , Short M. , Bonomi A.
Published: December 2016

This work involves the assessment of various pre‐treatment methods for the production of bioethanol in South Africa from sugarcane bagasse. The possibility of producing methane was also considered. The pre‐treatment methods that have been modelled are acid pre‐hydrolysis, steam explosion (acid‐catalysed and un‐catalysed), delignification with sodium hydroxide, acid hydrolysis and enzymatic hydrolysis. These pre‐treatment options were arranged in a superstructure, and optimization was performed by decomposing the superstructure into eight possible flowsheets. These flowsheets were then optimized in General Algebraic Modelling Systems by using economic and environmental objective functions sequentially. The solution space was used to evaluate the possible flowsheets in terms of both objectives. Steam explosion pre‐treatment would be recommended for the production of only methane. Acid hydrolysis can be added to steam explosion in order to produce glucose (for bioethanol production), and this increases profitability and reduces environmental impact of the steam explosion only flowsheet; however, the glucose flowrate from the steam explosion with acid hydrolysis flowsheet is low. The steam explosion with enzymatic hydrolysis flowsheet would be recommended to produce a higher glucose flowrate; however, the environmental impact of this flowsheet may be large if the electricity consumption of enzyme production is large. Copyright © 2016 Curtin University of Technology and John Wiley & Sons, Ltd.
Ancestral Variations in the Shape and Size of the Zygoma
Authors: Oettlé Anna C. , Demeter Fabrice P. , L'abbé Ericka N.
Published: December 2016

The variable development of the zygoma, dictating its shape and size variations among ancestral groups, has important clinical implications and valuable anthropological and evolutionary inferences. The purpose of the study was to review the literature regarding the variations in the zygoma with ancestry. Ancestral variation in the zygoma reflects genetic variations because of genetic drift as well as natural selection and epigenetic changes to adapt to diet and climate variations with possible intensification by isolation. Prominence of the zygoma, zygomaxillary tuberosity, and malar tubercle have been associated with Eastern Asian populations in whom these features intensified. Prominence of the zygoma is also associated with groups from Eastern Europe and the rest of Asia. Diffusion of these traits occurred across the Behring Sea to the Arctic areas and to North and South America. The greatest zygomatic projections are exhibited in Arctic groups as an adaptation to extreme cold conditions, while Native South American groups also present with other features of facial robusticity. Groups from Australia, Malaysia, and Oceania show prominence of the zygoma to a certain extent, possibly because of archaic occupations by undifferentiated Southeast Asian populations. More recent interactions with Chinese groups might explain the prominent cheekbones noted in certain South African groups. Many deductions regarding evolutionary processes and diversifications of early groups have been made. Cognisance of these ancestral variations also have implications for forensic anthropological assessments as well as plastic and reconstructive surgery. More studies are needed to improve accuracy of forensic anthropological identification techniques. Anat Rec, 300:196–208, 2017. © 2016 Wiley Periodicals, Inc.
The expression patterns of the clock genes period and timeless are affected by photoperiod in the Mediterranean corn stalk borer, Sesamia nonagrioides
Authors: Kontogiannatos Dimitrios , Gkouvitsas Theodoros , Kourti Anna
Published: December 2016

To obtain clues to the link between the molecular mechanism of circadian and photoperiod clocks, we cloned two circadian clock genes, period (per) and timeless (tim) from the moth Sesamia nonagrioides, which undergoes facultative diapause controlled by photoperiod. Sequence analysis revealed a high degree of conservation among the compared insects fοr both genes. We also investigated the expression patterns of per and tim in brains of larvae growing under 16L:8D (long days), constant darkness (DD) and 10L:14D (short days) conditions by qPCR assays. The results showed that mRNA accumulations encoding both genes exhibited diel oscillations under different photoperiods. The oscillation of per and tim mRNA, under short‐day photoperiod differed from long‐day. The difference between long‐day and short‐day conditions in the pattern of mRNA levels of per and tim appears to distinguish photoperiodic conditions clearly and both genes were influenced by photoperiod in different ways. We infer that not all photoperiodic clocks of insects interact with circadian clocks in the same fashion. Our results suggest that transcriptional regulations of the both clock genes act in the diapause programing in S. nonagrioides. The expression patterns of these genes are affected by photoperiod but runs with 24 h by entrainment to daily environmental cues.
Simulating Trial Trenches for Archaeological Prospection: Assessing the Variability in Intersection Rates
Authors: Haneca Kristof , Debruyne Sofie , Vanhoutte Sofie , Ervynck Anton , Vermeyen Maarten , Verhagen Philip
Published: December 2016

In this study we draw attention to the inherent variability in the results of trial trenching, when taking into account the countless variations in orientation and positioning of trenches. Grids of trial trenches were simulated time and again on the excavation plans of 16 archaeological sites from Flanders, Belgium. Orientation and positioning of the grid layout was shifted randomly, whilst the area coverage varied from 2.5% to 80%. The intersection rates of the archaeological features allow to gain more insight in trends and variability that are inherent to the chosen design of trial trenches. It is assessed how robust a chosen grid layout performs on (multi‐period) archaeological sites and how variable these results might be. The most effective layout appears to be a grid with short, parallel and discontinuous trenches or a standard grid, closely followed by 2 m wide continuous trenches. Implementing 4 m wide trenches reduces the effectiveness of the latter method substantially. When the area coverage of the trenches is below 10%, the results of the archaeological prospection become unreliable and can potentially lead to a substantial over‐or underestimation of the actual feature density on the site. Copyright © 2016 John Wiley & Sons, Ltd.
Metrics for openness
Authors: Nichols David M. , Twidale Michael B.
Published: December 2016

The characterization of scholarly communication is dominated by citation‐based measures. In this paper we propose several metrics to describe different facets of open access and open research. We discuss measures to represent the public availability of articles along with their archival location, licenses, access costs, and supporting information. Calculations illustrating these new metrics are presented using the authors’ publications. We argue that explicit measurement of openness is necessary for a holistic description of research outputs.
Understanding users of cloud music services: Selection factors, management and access behavior, and perceptions
Authors: Lee Jin Ha , Wishkoski Rachel , Aase Lara , Meas Perry , Hubbles Chris
Published: December 2016

Recent, rapid changes in technology have resulted in a proliferation of choices for music storage and access. Portable, web‐enabled music devices are widespread, and listeners now enjoy a plethora of options regarding formats, devices, and access methods. Yet in this mobile music environment, listeners' access and management strategies for music collections are poorly understood, because behaviors surrounding the organization and retrieval of music collections have received little formal study. Our current research seeks to enrich our knowledge of people's music listening and collecting behavior through a series of systematic user studies. In this paper we present our findings from interviews involving 20 adult and 20 teen users of commercial cloud music services. Our results contribute to theoretical understandings of users' music information behavior in a time of upheaval in music usage patterns, and more generally, the purposes and meanings users ascribe to personal media collections in cloud‐based systems. The findings suggest improvements to the future design of cloud‐based music services, as well as to any information systems and services designed for personal media collections, benefiting both commercial entities and listeners.
Free‐to‐publish, free‐to‐read, or both? Cost, equality of access, and integrity in science publishing
Authors: James Jack E.
Published: December 2016

The Internet has triggered transformational change in the dissemination of science in the form of a global transition to open access (OA) publishing. Heavy investment favoring Gold over Green OA has been associated with increased total publication costs, inequality of opportunity to publish, and concerns about integrity in science reporting. Notwithstanding current fluidity because of ongoing competition for market share between supporters of the major alternative publishing strategies, emerging trends indicate the need for material and human resources to be redirected away from Gold and toward Green OA. Doing so will reduce total publication costs, increase equality of access for authors and readers, and remove the financial incentives that have encouraged poor and corrupt publishing practices.
The scaling relationship between citation‐based performance and coauthorship patterns in natural sciences
Authors: Ronda‐Pupo Guillermo Armando , Katz J. Sylvan
Published: December 2016

The aim of this paper is to extend our knowledge about the power‐law relationship between citation‐based performance and coauthorship patterns in papers in the natural sciences. We analyzed 829,924 articles that received 16,490,346 citations. The number of articles published through coauthorship accounts for 89%. The citation‐based performance and coauthorship patterns exhibit a power‐law correlation with a scaling exponent of 1.20 ± 0.07. Citations to a subfield's research articles tended to increase 2.1.20 or 2.30 times each time it doubled the number of coauthored papers. The scaling exponent for the power‐law relationship for single‐authored papers was 0.85 ± 0.11. The citations to a subfield's single‐authored research articles increased 2.0.85 or 1.89 times each time the research area doubled the number of single‐authored papers. The Matthew Effect is stronger for coauthored papers than for single‐authored. In fact, with a scaling exponent <1.0 the impact of single‐authored papers exhibits a cumulative disadvantage or inverse Matthew Effect.
Recursive Generalized Maximum Correntropy Criterion Algorithm with Sparse Penalty Constraints for System Identification
Authors: Ma Wentao , Duan Jiandong , Chen Badong , Gui Guan , Man Weishi
Published: December 2016

To address the sparse system identification problem in a non‐Gaussian impulsive noise environment, the recursive generalized maximum correntropy criterion (RGMCC) algorithm with sparse penalty constraints is proposed to combat impulsive‐inducing instability. Specifically, a recursive algorithm based on the generalized correntropy with a forgetting factor of error is developed to improve the performance of the sparsity aware maximum correntropy criterion algorithms by achieving a robust steady‐state error. Considering an unknown sparse system, the l1‐norm and correntropy induced metric are employed in the RGMCC algorithm to exploit sparsity as well as to mitigate impulsive noise simultaneously. Numerical simulations are given to show that the proposed algorithm is robust while providing robust steady‐state estimation performance.