bluuebunny/crossref_metadata_2025 huggingface dataset:
Coating of polytetrafluoroethylene/polyacrylate: Core‐shelled structure and tribological behaviors
Authors: Wang Na , Wang Honggang , Ren Junfang , Gao Gui , Chen Shengsheng , Yang Yawen
Published: March 2019

In order to improve the tribological properties of polytetrafluoroethylene (PTFE), the core‐shelled PTFE/polyacrylate nanoparticles were prepared by seed emulsion polymerization and its tribological behaviors were investigated. The core–shell structure was determined by a Fourier transform infrared spectrometer and transmission electron microscopy. The results of thermoanalysis showed that polyacrylate had lost more weight than PTFE/polyacrylate composite above 300 °C, which indicated an improvement in the thermal stability. Moreover, the friction and wear results indicated that friction coefficient of PTFE/polyacrylate coating keeps at a relatively lower level, which is between that of PTFE and polyacrylate, and the wear volume is the smallest, so that an excellent performance of low friction and wear resistance was demonstrated. Besides, the tribological properties of the core‐shelled coating are maintained to be stable under high load or high speed. Therefore, the core‐shelled nanoparticles would be potential to polymer coating as high‐performance solid lubricants. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47774.
Hydrolysis of poly(l‐lactide)/ZnO nanocomposites with antimicrobial activity
Authors: Pérez‐Álvarez Leyre , Lizundia Erlantz , Ruiz‐Rubio Leire , Benito Vanessa , Moreno Isabel , Vilas‐Vilela José Luis
Published: March 2019

This work investigates the effect of the incorporation of zinc oxide (ZnO) nanoparticles within a poly(l‐lactic acid) (PLLA) matrix as an approach to speed up the hydrolysis of PLLA film surfaces. Hydrolysis was done by immersing nanocomposite films having 1 wt % of ZnO in 0.25 M sodium hydroxide at 58 °C. This concentration has been selected as it provides the maximum changes of physicochemical properties of hosting PLLA matrix. The evolution of the thermal properties, ultraviolet–visible transparency, wettability, and morphology were monitored at different time points. The amount of carboxylic groups onto PLLA/ZnO surfaces was quantified according to Toludine Blue‐O assay. Hydrolysis was mainly limited to film surfaces, which were grafted by carboxylic groups as a result of the random scission of PLLA ester linkages. The presence of such functional groups decreases the inherent surface hydrophobicity of PLLA at short hydrolysis times. On the contrary, long hydrolyses increase the hydrophobicity as a result of surface nanostructuring induced by the degradation of PLLA to water‐soluble oligomers. Overall, ZnO nanoparticles enable shorter surface modification times and provide a quick approach for the modification on the polarity of polylactide surfaces. The potential of hydrolyzed films as antimicrobial materials was explored using Gram‐negative Escherichia coli as a model. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47786.
Long‐Term Physical Activity and Subsequent Risk for Rheumatoid Arthritis Among Women: A Prospective Cohort Study
Authors: Liu Xinyi , Tedeschi Sara K. , Lu Bing , Zaccardelli Alessandra , Speyer Cameron B. , Costenbader Karen H. , Karlson Elizabeth W. , Sparks Jeffrey A.
Published: March 2019

Objective

To evaluate the effects of long‐term physical activity on subsequent risk of rheumatoid arthritis (RA) in a prospective cohort study.

Methods

This study investigated physical activity and RA risk among women from the Nurses' Health Study II (1989–2015). Physical activity exposures and covariates were prospectively obtained using biennial questionnaires. Two rheumatologists independently reviewed the medical records of women who self‐reported a new diagnosis of RA on biennial questionnaires and who screened positive for RA based on a supplemental survey. All incident RA cases met the 1987 American College of Rheumatology (ACR) or 2010 ACR/European League Against Rheumatism (EULAR) classification criteria for RA. The primary analysis investigated the long‐term cumulative average number of hours spent in recreational physical activity 2–8 years prior to the RA diagnosis, a time span chosen to reduce the potential for reverse causation bias, since early RA affects physical activity prior to diagnosis. Estimated Cox regression hazard ratios (HRs) with 95% confidence intervals (95% CIs) were used to assess the risk of RA serologic phenotypes (all, seropositive, or seronegative) in relation to physical activity categories. The analyses were adjusted for body mass index (BMI) at age 18 years and time‐varying potential confounders, and the mediating effect of updated BMI on the interaction between physical activity and RA risk was quantified.

Results

Among the 113,366 women analyzed, 506 incident RA cases (67.0% with seropositive RA) were identified during 2,428,573 person‐years of follow‐up. After adjustment for confounders, including smoking, dietary quality, and BMI at age 18 years, increasing cumulative average total hours of recreational physical activity was associated with a reduced risk of RA, as follows: HR 1.00 for <1 hour/week (reference), HR 1.00 (95% CI 0.78–1.29) for 1 to <2 hours/week, HR 0.92 (95% CI 0.72–1.17) for 2 to <4 hours/week, HR 0.84 (95% CI 0.63–1.12) for 4 to <7 hours/week, and HR 0.67 (95% CI 0.47–0.98) for ≥7 hours/week (P for trend = 0.02). The proportion of the effect between physical activity and RA mediated by updated BMI was 14.0% (P = 0.002) for all RA and 20.0% (P = 0.001) for seropositive RA.

Conclusion

Higher levels of physical activity were associated with reduced RA risk. These results add to the literature implicating metabolic factors in the pathogenesis of RA.
Musculoskeletal Anatomy Knowledge Retention in the Macquarie University Chiropractic Program: A Cross‐Sectional Study
Authors: Hulme Anneliese K. , Luo Kehui , Štrkalj Goran
Published: March 2019

Attrition of anatomy knowledge has been an area of concern in health professions curricula. To ensure safe and effective clinical practice, the study of chiropractic requires a good knowledge of musculoskeletal anatomy. In this study, musculoskeletal limb knowledge retention was investigated among students in the 5‐year chiropractic program at Macquarie University, Australia. A test of 20 multiple‐choice questions, categorized into low‐order (LO) and high‐order (HO) cognitive ability according to Bloom’s Taxonomy, was developed. Students enrolled in the program were invited to participate with 257 of the 387 choosing to participate, (response rate ranging 56%–72% per year level). No attrition of knowledge across the years was observed, instead, a significant increase in knowledge, measured by total LO and HO scores (P < 0.0005), throughout the program. There were significant increases in both low and high cognitive scores which were not uniform, with high‐order scores increasing significantly in the last two year levels. The increase of knowledge, may be explained, at least partially, by the vertical and horizontal integrated curriculum. Retrieval of knowledge, especially in clinically applied formats, may have led to an enhanced ability to apply anatomy knowledge and account for the increased scores in the high‐order knowledge seen in the later clinical years. Evaluating anatomy knowledge retention at different cognitive levels seems to provide a better assessment and is worth considering in future anatomy educational research.
The new 4‐m robotic telescope
Authors: Gutiérrez C. M. , Arnold D. , Copley D. , Copperwheat C. M. , Harvey E. , Jermak H. , Knapen J. , McGrath A. , Oria A. , Rebolo R. , Steele I. A. , Torres M.
Published: March 2019

We present a project to build a 4‐m‐diameter telescope (New Robotic Telescope [NRT]) with fully robotic operation. The telescope will be sited at the Observatory of Roque de los Muchachos in the island of La Palma (Spain). When it enters into operation in 5 years' time, it will be likely the largest robotic telescope in the world. This, in conjunction with the extremely fast response and the versatile and flexible instrumentation in the optical and near‐infrared ranges, will make the NRT a world‐leading facility in the area of time‐domain astrophysics. Here we discuss some of the main scientific cases, the mechanical and optical design, the control system, first light instrumentation, and the timeline of the project.
Multi‐messenger observations of supermassive black holes binary mergers
Authors: Pereira F. A. C. , Rodrigues I. , Alves M. E. S. , Lodato G. , Price D.
Published: March 2019

When a circumprimary gaseous disk is pushed into the primary supermassive black hole (SMBH) by the tidal force of the decaying secondary black hole, it can produce an increase in the luminosity. In the case of a disk that lies in the same plane of the SMBHs binary, that luminosity exceeds the Eddington limit. In this paper, we extend these previous investigations to the case of systems misaligned with different mass values for the binary components. Our aim is to probe which mass range can produce stronger electromagnetic counterparts in the last stages of coalescence. We concentrate in geometrically thin disk models and binary SMBHs with mass ratio q = 10−3. We compare our numerical results with previously obtained analytical results in the literature. Disks misaligned surrounding a primary SMBH can lead to an electromagnetic signature of the gravitational wave signal emitted from final stages of the SMBH's binary orbital decay.
Baryon number violation searches in neutrino experiments
Authors: Raaf J. L.
Published: March 2019

This paper presents a discussion of methods to search for nucleon (proton and bound neutron) decay in existing and future neutrino experiments. So far, no experiment has seen strong evidence of nucleon decay, but it is well motivated by various theoretical models, and detection would represent a profound impact on our understanding of the universe.
The short wavelength instrument for the polarization explorer balloon‐borne experiment: Polarization modulation issues
Authors: Columbro F. , Battistelli E. S. , Coppolecchia A. , D'Alessandro G. , de Bernardis P. , Lamagna L. , Masi S. , Pagano L. , Paiella A. , Piacentini F. , Presta G.
Published: March 2019

In this paper we investigate the impact of using a polarization modulator in The Short Wavelength Instrument for the Polarization Explorer (SWIPE) of the large scale polarization explorer (LSPE). The experiment is optimized to measure the linear polarization of the cosmic microwave background at large angular scales during a circumpolar long‐duration stratospheric balloon mission, and uses multimode bolometers cooled to .3 K. The 330 detectors cover three bands at 140, 220, and 240 GHz. Polarimetry is achieved by means of a large rotating half‐wave plate (HWP) and a single wire‐grid polarizer in front of the arrays. The polarization modulator is the first polarization‐active component of the optical chain, reducing significantly the effect of instrumental polarization. A trade‐off study comparing stepped versus spinning HWPs drives the choice towards the second. Modulating the cosmic microwave background polarization signal at four times the spin frequency moves it away from 1/f noise from the detectors and the residual atmosphere. The HWP is cooled to 1.6 K to reduce the background on the detectors. Furthermore, its polarized emission combined with the emission of the polarizer produces spurious signals modulated at 2f and 4f. The 4f component is synchronous with the signal of interest and has to characterized to be removed from cosmological data.
The equilibrium equations of Boson‐Fermi systems in the Newtonian approximation
Authors: Gao Z. F. , Song D. L. , Li X. D. , Shan H. , Wang N.
Published: March 2019

There is accumulating evidence that scalar fields may exist in nature. The gravitational collapse of a boson cloud leads to the formation of a boson star just like white dwarfs and neutron stars. In general, as one of the candidates of dark matter, a boson star holds a stable configuration and has deserved intensive attention and extensive research in the past 50 years. At first, we analyze the ground state solutions for a Boson‐Fermi system using the metric tensor in the Newtonian approximation, then analyze the configuration of a star composed of bosons and fermions. At last, for the purpose of investigating the equilibrium geometry of a Boson‐Fermi system, we construct the virial equations of a boson‐Fermi system with different orders. In our future work, we will explore the equilibrium configuration and the stability of a Boson‐Fermi star and how a scalar field affects the pressure of the system using higher‐order virial equations of fluid motions.
Disk structure of cataclysmic variables and broadband noise characteristics in comparison with XRBs
Authors: Balman Ş.
Published: March 2019

Flicker noise and its variations in accreting systems have been a diagnostic tool in understanding accretion disk structure and state transitions. I present broadband noise variations of nonmagnetic cataclysmic variables (CVs) in comparison with magnetic CVs (MCV) extrapolating the comparisons into X‐ray binaries (XRB), mostly in the X‐ray wavelengths. CVs demonstrate band‐limited noise in the UV and X‐ray energy bands (and also optical), which can be adequately explained in the framework of the model of propagating fluctuations). The detected frequency breaks in the nonmagnetic CVs are in the range 1–6 mHz in quiescence and indicate an optically thick disk truncation (i.e., transition) showing the existence of advective (ADAF‐like) hot flows in the inner regions. Analysis of other available data (e.g., SS Cyg, SU UMa, WZ Sge, and Z Cha) reveals that during the outburst the inner disk radius moves toward the white dwarf and recedes as the outburst declines (with some exceptions) while changes in the X‐ray energy spectrum are also observed. Cross‐correlations between the simultaneous optical, UV, and X‐ray light curves show time lags consistent with truncated optically thick disk‐like and ADAF‐like hot flows in the inner disk. I also discuss the hysteresis effect in dwarf novae and show that the X‐ray temperatures and break frequencies anticorrelate indicating the energy exchange in the disk flow as the accretion state of the source changes.
Short report: Relationships between sensory processing, repetitive behaviors, anxiety, and intolerance of uncertainty in autism spectrum disorder and Williams syndrome
Authors: Glod Magdalena , Riby Deborah M. , Rodgers Jacqui
Published: March 2019

Autism spectrum disorder (ASD) and Williams syndrome (WS) share psychopathology relating to sensory processing and repetitive behaviors. The relationships between the sensory features and repetitive behaviors in both disorders, and the mechanisms underlying these relationships are not well understood. The aim of this study was to examine the relationships between sensory processing, repetitive behaviors, anxiety, and intolerance of uncertainty in children with ASD and those with WS to better understand the complexity of psychopathology in these disorders. Parents of 19 children with ASD and 16 children with WS, aged between 4 and 9 years, were asked to complete questionnaires assessing their children's sensory experiences, anxiety symptoms, severity and frequency of repetitive behaviors, and level of intolerance of uncertainty. Serial mediation analysis was performed. Direct significant relationships between sensory features and repetitive behaviors were found only for the ASD group. The relationship between sensory processing difficulties and repetitive behaviors was mediated via intolerance of uncertainty in WS. The findings support the value of considering the complexity of the mechanisms underlying the relationship between sensory processing and repetitive behaviors across neurodevelopmental disorders and the mechanisms underlying these aspects of psychopathology in these groups. Understanding these relationships will shed light on some of the most challenging and intractable characteristics of both conditions and inform suitable interventions to improve quality of life for individuals with either ASD or WS. Autism Research 2019, 12: 759–765. © 2019 International Society for Autism Research, Wiley Periodicals, Inc.

Lay Summary

In autism spectrum disorder (ASD) and Williams syndrome (WS) difficulties processing the sensory aspects of the environment, repetitive behaviors and high levels of anxiety co‐occur, but the relationships between these features are not well understood. This study found that sensory difficulties were directly associated with repetitive behaviors in children with ASD, but not WS, and in WS this relationship was mediated by intolerance of uncertainty. The findings support the value of considering the complexity of the mechanisms underlying the relationship between sensory processing and repetitive behaviors across neurodevelopmental disorders.
Development and identification of a fully human single‐chain variable fragment 29 against TSLP
Authors: Nian Siji , Zhu Jianguang , Yu Hong , Chen Qi , Ye Yingchun , Cao Xinmei , Yuan Qing
Published: March 2019

Thymic stromal lymphopoietin is a key initiator for inducing Th2‐type inflammation and a potential therapeutic target for allergic disease. In the present study, the naive human antibody library was enriched using human thymic stromal lymphopoietin (hTSLP) as an antigen by phage display. Single clones were randomly picked from the enriched antibody library after three rounds of selection, and these were expressed for enzyme‐linked immunosorbent assay (ELISA). The positive single‐chain fragment variables (scFvs) determined by ELISA were further identified by Western blot, Biacore, and flow cytometry. After three rounds of phage display, 35% of the scFv clones were positive by ELISA and could bind well with hTSLP. Further identification revealed that scFv29 had satisfactory characteristics. The scFv29 was specific to hTSLP, and had no cross‐reaction with hIL‐33, hIL‐4, and hIL‐13. The scFv29 could bind to hTSLP in competition with the TSLP receptor and could also bind to mouse TSLP. Cellular experiments revealed that mTSLP could stimulate myeloid dendritic cell (DC) to mature, and scFv29 blocking could reduce the maturation rate of DC. These findings suggest that scFv29 could be used as a neutralizing antibody to block the signaling of TSLP, and this work provides the foundation for further study of the therapeutic roles of TSLP in allergic inflammation diseases.
General Synthesis of Heteroatom‐Doped Hierarchical Carbon toward Excellent Electrochemical Energy Storage
Authors: Zou Guoqiang , Hou Hongshuai , Hu Jiugang , Ji Xiaobo
Published: March 2019

Heteroatom‐doping is an effective approach to modify the microstructure of carbon‐based materials toward enhanced electrochemical energy storage performance. Nevertheless, it is a great challenge to obtain a specific heteroatom‐doped carbon material with hierarchical structure as a general doping strategy is missing. Herein, carbon materials doped with P, S and both of them are designed and precisely prepared through in‐situ polymerization. Used as anode for sodium‐ion batteries, the best performing material displays a high specific capacity of 368.6 mAh g−1 at a current density of 0.1 A g−1 after 100 cycles. A high capacity of 159.8 mAh g−1 is achieved at a large current density of 5 A g−1. Impressively, this material also delivers robust storage performances for lithium. According to the first‐principles method and detailed experimental data, the expanded interlayer distance and enhanced electronic conductivity of the microcrystalline region can be attributed to C−S and P−C bonds, while the high surface capacitance contribution can be assigned to surface C−S species and highly exposed edges of the microcrystalline region. This work sheds light on a promising method for the exploitation of versatile heteroatom modified hierarchical carbon materials.
Short‐term effects experienced during examinations in an actively shielded 7 T MR
Authors: Hansson Boel , Höglund Peter , Markenroth Bloch Karin , Nilsson Markus , Olsrud Johan , Wilén Jonna , Björkman‐Burtscher Isabella M.
Published: March 2019

The objective of this study was to evaluate occurrence and strength of short‐term effects experienced by study participants in an actively shielded (AS) 7 tesla (7 T) magnetic resonance (MR) scanner, to compare results with earlier reports on passively shielded (PS) 7 T MR scanners, and to outline possible healthcare strategies to improve patient compliance. Study participants (n = 124) completed a web‐based questionnaire directly after being examined in an AS 7 T MR (n = 154 examinations). Most frequently experienced short‐term effects were dizziness (84%) and inconsistent movement (70%), especially while moving into or out of the magnet. Peripheral nerve stimulation (PNS)—twitching—was experienced in 67% of research examinations and showed a dependence between strength of twitches and recorded predicted PNS values. Of the participants, 74% experienced noise levels as acceptable and the majority experienced body and room temperature as comfortable. Of the study participants, 95% felt well‐informed and felt they had had good contact with the staff before the examination. Willingness to undergo a future 7 T examination was high (>90%). Our study concludes short‐term effects are often experienced during examinations in an AS 7 T MR, leaving room for improvement in nursing care strategies to increase patient compliance. Bioelectromagnetics. 2019;9999:XX–XX. © 2019 The Authors. Bioelectromagnetics Published by Wiley Periodicals, Inc.
Neuland in Planung und Realisierung: Die Kelchstützen des neuen Stuttgarter Hauptbahnhofs
Authors: Bechmann Roland , Schmid Angelika , Noack Torsten , Sobek Werner
Published: March 2019

Im Rahmen des Bahnprojekts Stuttgart–Ulm wird der Stuttgarter Hauptbahnhof komplett umgebaut und erneuert. Der alte Kopfbahnhof wird hierbei durch einen unterirdischen Durchgangsbahnhof ersetzt. Wesentliches Gestaltungselement der neuen Bahnsteighalle sind die sogenannten Kelchstützen. Diese tragen nicht nur das Schalendach, sondern dienen auch der natürlichen Belichtung und Belüftung des Innenraums. Der vorliegende Beitrag beschreibt Formfindung und Berechnung dieser einzigartigen Geometrien und erläutert, wie durch die Tragwerksplanung eine technisch und ökonomisch nachhaltige Umsetzung ermöglicht wurde.
Impact of RNA–Protein Interaction Modes on Translation Control: The Versatile Multidomain Protein Gemin5
Authors: Francisco‐Velilla Rosario , Azman Embarc‐Buh , Martinez‐Salas Encarnacion
Published: March 2019

The fate of cellular RNAs is largely dependent on their structural conformation, which determines the assembly of ribonucleoprotein (RNP) complexes. Consequently, RNA‐binding proteins (RBPs) play a pivotal role in the lifespan of RNAs. The advent of highly sensitive in cellulo approaches for studying RNPs reveals the presence of unprecedented RNA‐binding domains (RBDs). Likewise, the diversity of the RNA targets associated with a given RBP increases the code of RNA–protein interactions. Increasing evidence highlights the biological relevance of RNA conformation for recognition by specific RBPs and how this mutual interaction affects translation control. In particular, noncanonical RBDs present in proteins such as Gemin5, Roquin‐1, Staufen, and eIF3 eventually determine translation of selective targets. Collectively, recent studies on RBPs interacting with RNA in a structure‐dependent manner unveil new pathways for gene expression regulation, reinforcing the pivotal role of RNP complexes in genome decoding.
The effect of carbon dissemination on cost of equity
Authors: Albarrak Mohammed S. , Elnahass Marwa , Salama Aly
Published: March 2019

This study examines whether firms can influence their cost of equity (COE) by broadly disseminating their carbon information over Twitter. We study firms' dissemination decisions of carbon information by developing a comprehensive measure of carbon information that a firm makes on Twitter, referred to as iCarbon. Using a sample of 1,737 firm‐year observations for 584 nonfinancial firms with a Twitter account and listed on the U.S. NASDAQ stock exchange over the period 2009–2015, we find that iCarbon is significantly and negatively associated with COE. Our results are consistent after determining the effect of Bloomberg's environmental and environmental, social, and governance disclosure. The findings also hold when using alternative measures of COE and iCarbon.
Artificially Linked Ubiquitin Dimers Characterised Structurally and Dynamically by NMR Spectroscopy
Authors: Zhao Xiaohui , Mißun Maite , Schneider Tobias , Müller Franziska , Lutz Joachim , Scheffner Martin , Marx Andreas , Kovermann Michael
Published: March 2019

As one of the most prevalent post‐translational modifications in eukaryotic cells, ubiquitylation plays vital roles in many cellular processes, such as protein degradation, DNA metabolism, and cell differentiation. Substrate proteins can be tagged by distinct types of polymeric ubiquitin (Ub) chains, which determine the eventual fate of the modified protein. A facile, click chemistry based approach for the efficient generation of linkage‐defined Ub chains, including Ub dimers, was recently established. Within these chains, individual Ub moieties are connected through a triazole linkage, rather than the natural isopeptide bond. Herein, it is reported that the conformation of an artificially K48‐linked Ub dimer resembles that of the natively linked dimer, with respect to structural and dynamic characteristics, as demonstrated by means of high‐resolution NMR spectroscopy. Thus, it is proposed that artificially linked Ub dimers, as generated by this approach, represent potent tools for studying the inherently different properties and functions of distinct Ub chains.
Crystallization Mechanisms and Rates of Cyclopentane Hydrates Formation in Brine
Authors: Ho-Van Son , Bouillot Baptiste , Garcia Daniel , Douzet Jérome , Cameirao Ana , Maghsoodloo-Babakhani Saheb , Herri Jean-Michel
Published: March 2019

Clathrate hydrates most often grow at the interface between liquid water and another fluid phase (hydrocarbon) acting as a provider for the hydrate guest molecules, and some transfer through this shell is required for the hydrate growth to proceed, thus self‐limiting the reaction rate. An optical microscope and a horizontal reaction cell are utilized to capture the shell growth phenomenology and to estimate the hydrate layer growth rates from sequential pictures. Cyclopentane (CP) is chosen as the hydrate‐forming molecule to obtain hydrates at low pressure. Experimental hydrate layer growth rates are provided for the CP+brine system, using various combinations of salts and degrees of subcooling.
Adsorbed States of Hydrogen on Platinum: A New Perspective
Authors: Parker Stewart F. , Mukhopadhyay Sanghamitra , Jiménez‐Ruiz Mónica , Albers Peter W.
Published: March 2019

The interaction of hydrogen with platinum is enormously important in many areas of catalysis. The most significant of these are in polymer electrolyte membrane fuel cells (PEMFC), in which carbon‐supported platinum is used to dissociate hydrogen gas at the anode. The nature of adsorbed hydrogen on platinum has been studied for many years on single‐crystal surfaces, on high‐surface area‐platinum metal (Raney platinum and platinum black), and on supported catalysts. Many forms of vibrational spectroscopy have played a key role in these studies, however, there is still no clear consensus as to the assignment of the spectra. In this work, ab initio molecular dynamics (AIMD) and lattice dynamics were used to study a 1.1 nm nanoparticle, Pt44H80. The results were compared to new inelastic neutron scattering spectra of hydrogen on platinum black and of a carbon‐supported platinum fuel cell catalyst and an assignment scheme that rationalises all previous data is proposed.
Making the Silylation of Alcohols Chiral: Asymmetric Protection of Hydroxy Groups
Authors: Seliger Jan , Oestreich Martin
Published: March 2019

The non‐enzymatic kinetic resolution of racemic mixtures of alcohols by silylation had been unknown before the turn of the century. This stands in stark contrast to established acylation techniques. The same applies to the related desymmetrization of diols. This might come as a surprise, given the significance of silyl ethers as protecting groups in multistep synthesis of complex molecules. The situation changed after a seminal report by Ishikawa nearly twenty years ago. Since then, enantioselective silylation of alcohols has matured and grown into an independent research field with organocatalytic and transition‐metal‐catalyzed approaches providing powerful solutions. This Minireview summarizes these recent advances with particular emphasis on the stereoselective dehydrogenative coupling of alcohols and hydrosilanes.
Enhanced in vivo Optical Imaging of the Inflammatory Response to Acute Liver Injury in C57BL/6 Mice Using a Highly Bright Near‐Infrared BODIPY Dye
Authors: Sirbu Dumitru , Luli Saimir , Leslie Jack , Oakley Fiona , Benniston Andrew C.
Published: March 2019

Delving deeper is possible in whole‐body in vivo imaging using a super‐bright membrane‐targeting BODIPY dye (BD). The dye was used to monitor homing of ex vivo fluorescently labelled neutrophils to an injured liver of dark‐pigmented C57BL/6 mice. In vivo imaging system (IVIS) data conclusively showed an enhanced signal intensity and a higher signal‐to‐noise ratio in mice receiving neutrophils labelled with the BD dye relative to those labelled with a gold standard dye at 2 h post in vivo administration of fluorescently labelled cells. Fluorescence‐activated cell sorting (FACS) confirmed that BD is nontoxic, and an exceptional cell labelling dye that opens up precision deep‐organ in vivo imaging of inflammation in mice routinely used for biomedical research. The origin of enhanced performance is identified with the molecular structure and the distinct localisation of the dye within cells that enable remarkable changes in its optical parameters.
Central and peripheral innervation patterns of defined axial motor units in larval zebrafish
Authors: Bello‐Rojas Saul , Istrate Ana E. , Kishore Sandeep , McLean David L.
Published: March 2019

Spinal motor neurons and the peripheral muscle fibers they innervate form discrete motor units that execute movements of varying force and speed. Subsets of spinal motor neurons also exhibit axon collaterals that influence motor output centrally. Here, we have used in vivo imaging to anatomically characterize the central and peripheral innervation patterns of axial motor units in larval zebrafish. Using early born “primary” motor neurons and their division of epaxial and hypaxial muscle into four distinct quadrants as a reference, we define three distinct types of later born “secondary” motor units. The largest is “m‐type” units, which innervate deeper fast‐twitch muscle fibers via medial nerves. Next in size are “ms‐type” secondaries, which innervate superficial fast‐twitch and slow fibers via medial and septal nerves, followed by “s‐type” units, which exclusively innervate superficial slow muscle fibers via septal nerves. All types of secondaries innervate up to four axial quadrants. Central axon collaterals are found in subsets of primaries based on soma position and predominantly in secondary fast‐twitch units (m, ms) with increasing likelihood based on number of quadrants innervated. Collaterals are labeled by synaptophysin‐tagged fluorescent proteins, but not PSD95, consistent with their output function. Also, PSD95 dendrite labeling reveals that larger motor units receive more excitatory synaptic input. Collaterals are largely restricted to the neuropil, however, perisomatic connections are observed between motor units. These observations suggest that recurrent interactions are dominated by motor neurons recruited during stronger movements and set the stage for functional investigations of recurrent motor circuitry in larval zebrafish.
Structural Aspects of the O‐glycosylation Linkage in Glycopeptides via MD Simulations and Comparison with NMR Experiments
Authors: Turupcu Aysegül , Diem Matthias , Smith Lorna J. , Oostenbrink Chris
Published: March 2019

A powerful conformational searching and enhanced sampling simulation method, and unbiased molecular dynamics simulations have been used along with NMR spectroscopic observables to provide a detailed structural view of O‐glycosylation. For four model systems, the force‐field parameters can accurately predict experimental NMR observables (J couplings and NOE's). This enables us to derive conclusions based on the generated ensembles, in which O‐glycosylation affects the peptide backbone conformation by forcing it towards to an extended conformation. An exception is described for β‐GalNAc‐Thr where the α content is increased and stabilized via hydrogen bonding between the sugar and the peptide backbone, which was not observed in the rest of the studied systems. These observations might offer an explanation for the evolutionary preference of α‐linked GalNAc glycosylation instead of a β link.
Evaluation of Compound Activity in Primary Human Intestinal Organoids Using Gene Expression and Histology
Authors: Marchelletta Ronald , Yu Jingxue , Moon Clara , Kim Mihee M.
Published: March 2019

Human intestinal organoids have enabled performance of functional epithelial studies and modeling of human diseases of the intestine. This unit describes 1) a method to isolate and culture crypts from human intestinal tissue, 2) use of combinatorial methods to expand stem cell–enriched spheroids and differentiate them into organoids composed of various intestinal epithelial cell types, and 3) methods to stimulate these organoids with and measure their responsiveness to external stimuli. To validate the differentiation, organoids can be stained to qualitatively evaluate the presence of colonic crypt morphology and specialized epithelial cell markers. These organoids are responsive to challenge with tumor necrosis factor α (TNFα), resulting in cytokine‐induced apoptosis. TNFα‐driven apoptosis can be blocked by a small‐molecule inhibitor of Ire1α (4μ8C), an endoplasmic‐reticulum stress sensor. This is one example of how the human intestinal organoid model can be a powerful tool to elucidate important biological pathways involved in human disease in intestinal epithelial cells. © 2019 by John Wiley & Sons, Inc.
Iron–PNP‐Pincer‐Catalyzed Transfer Dehydrogenation of Secondary Alcohols
Authors: Budweg Svenja , Wei Zhihong , Jiao Haijun , Junge Kathrin , Beller Matthias
Published: March 2019

The well‐defined iron PNP pincer complex catalyst [Fe(H)(BH4)(CO)(HN{CH2CH2P(iPr)2}2] was used for the catalytic dehydrogenation of secondary alcohols to give the corresponding ketones. Using acetone as inexpensive hydrogen acceptor enables the oxidation with good to excellent yields. DFT computations indicate an outer‐sphere mechanism and support the importance of an acceptor to achieve this transformation under milder conditions.
Fine‐needle aspiration of dermatofibrosarcoma protuberans metastasizing to hemithorax with superior vena cava compression: Case report and literature review
Authors: Banach Bridget S. , Antic Tatjana , Bridge Julia A. , Cipriani Nicole A. , Frye Laura , Krausz Thomas N. , Biernacka Anna
Published: March 2019

Dermatofibrosarcoma protuberans (DFSP) is a low‐grade spindle cell tumor of the skin commonly arising on the trunk and extremities which tends to be slow growing yet locally aggressive. DFSPs are associated with a good prognosis when surgical excision with negative margins is achieved. Although local recurrences occur up to 50% of incompletely resected cases, distant metastases are very rare. Here, we report a case of DFSP metastasizing to the right hemithorax diagnosed by an endobronchial ultrasound‐guided fine‐needle aspiration (FNA) 9 years after initial presentation. The aspirate showed a bland spindle cell proliferation that was morphologically similar to the original skin excision; the storiform pattern was particularly prominent in tumor‐tissue fragments in the cellblock. Immunostaining showed strong, diffuse positivity for CD34. Molecular studies demonstrated a characteristic COL1A1/PDGFB fusion in both original and metastatic specimens. A review of the literature revealed that metastatic DFSP most often involves the lungs, occurs usually in cases with fibrosarcomatous transformation and after a local recurrence, and presents on average 4.5 years after the original diagnosis. This case did not show fibrosarcomatous transformation or local recurrence prior to metastasis 9 years later. In summary, it is important to consider the potential for metastases years after a nonrecurring primary DFSP, despite its rarity. Cytologic features when complemented by ancillary studies and awareness of the patient's prior clinical history permit a confident diagnosis of metastatic DFSP by FNA. In addition, by confirming the characteristic translocation, tyrosine‐kinase inhibitor imatinib can provide additional treatment options for unresectable metastatic DFSP.
A new automated assay for the detection of synthetic urine in drug testing
Authors: Silva Fabiola , Kaileh Issa , Hobbs Gregory A.
Published: March 2019

Urine drug testing can be subject to attempts to dilute, adulterate, or substitute the specimen. Substitution may involve the use of commercially available synthetic urine. Current laboratory methods to detect specimen validity often fail to detect these products. We evaluated a new automated assay designed to detect synthetic urine. We determined that the assay met performance requirements and accurately identified five commercially obtained products as synthetic urine while not identifying known normal urine as synthetic. However, in a group of 843 patient urine samples, 40 of the 46 urine samples identified as “synthetic” were samples with creatinine <50 mg/dL. Fourteen of the 40 were actually positive for drugs of abuse. We conclude that the test is analytically valid but clinically limited. We recommend that it be used in conjunction with other indicators of synthetic urine. We suggest a scheme that would achieve this, and reporting terminology that would reflect the limits of the analysis.
Ecological and sociopolitical assessment of congressional and presidential designation of federal protected areas
Authors: Creech Tyler G. , Williamson Matthew A.
Published: March 2019

Protected areas are one of the most effective means by which biodiversity is conserved, but are often criticized for either neglecting the importance of local communities or sacrificing conservation objectives for political expedience. In the United States, federal protected areas can be designated via a democratic legislation process or via executive action, which allows for comparison of the ecological and sociopolitical context of these top‐down and bottom‐up processes. We compared protected areas resulting from congressional designation vs. presidential designation with respect to their ecological context (using measures of biodiversity and climate refugial potential) and sociopolitical context (using measures of local support for conservation and reliance on natural resource‐based industries). We found minimal differences between these designation modes for both ecological and sociopolitical variables. These results suggest that presidentially designated protected areas tend to be no more burdensome to local communities and no less valuable for ecological conservation than more widely accepted federal protected areas such as national parks, and they provide new evidence to inform the current debate over national monuments.
How soil granulometry, temperature, and water predict genetic differentiation in Namibian spiders (Ariadna: Segestriidae) and explain their behavior
Authors: Conti Erminia , Mulder Christian , Pappalardo Anna Maria , Ferrito Venera , Costa Giovanni
Published: March 2019

The Namib Desert is a biodiversity hotspot for many invertebrates, including spiders. Tube‐dwelling spiders belonging to the Ariadna genus are widespread in gravel plains. These sit‐and‐wait predators share a particular behavior, as they spend their life in tunnels in the soil, surrounding the entrance of their burrow with stone rings. We investigated five spider populations taking into account environmental parameters, functional traits, and molecular data. We have chosen the temperature at the soil surface and at the bottom of the burrow, the air humidity, and the soil granulometry to define the environment. The chosen functional traits were the diameter and depth of the burrows, the ratio between weight and length, the thermal properties of their silks, and the number of ring elements. The molecular branch lengths and the evolutionary distance emerging from cytochrome oxidase I gene sequences summarized the molecular analysis. Our study highlights a strong coherence between the resulting evolutionary lineages and the respective geographical distribution. Multivariate analyses of both environmental and molecular data provide the same phylogenetic interpretation. Low intrapopulation sequence divergence and the high values between population sequence divergence (between 4.9% and 26.1%) might even suggest novel taxa which deserve further investigation. We conclude that both the Kimura distance and the branch lengths are strengthening the environmental clustering of these peculiar sites in Namibia.
A practical tool for assessing ecosystem services enhancement and degradation associated with invasive alien species
Authors: Martinez‐Cillero Rocio , Willcock Simon , Perez‐Diaz Alvaro , Joslin Emma , Vergeer Philippine , Peh Kelvin S.‐H.
Published: March 2019

Current approaches for assessing the effects of invasive alien species (IAS) are biased toward the negative effects of these species, resulting in an incomplete picture of their real effects. This can result in an inefficient IAS management. We address this issue by describing the INvasive Species Effects Assessment Tool (INSEAT) that enables expert elicitation for rapidly assessing the ecological consequences of IAS using the ecosystem services (ES) framework. INSEAT scores the ecosystem service “gains and losses” using a scale that accounted for the magnitude and the reversibility of its effects. We tested INSEAT on 18 IAS in Great Britain. Here, we highlighted four case studies:Harmonia axyridis(Harlequin ladybird),Astacus leptodactylus(Turkish crayfish),Pacifastacus leniusculus(Signal crayfish) andImpatiens glandulifera(Himalayan balsam). The results demonstrated that a collation of different experts’ opinions using INSEAT could yield valuable information on the invasive aliens’ ecological and social effects. The users can identify certain IAS as ES providers and the trade‐offs between the ES provision and loss associated with them. This practical tool can be useful for evidence‐based policy and management decisions that consider the potential role of invasive species in delivering human well‐being.
What has become of the refugia hypothesis to explain biological diversity in Amazonia?
Authors: Rocha Daniel Gomes da , Kaefer Igor L.
Published: March 2019

The spatial distribution of biodiversity and related processes is the core of Biogeography. Amazonia is the world's most diverse rainforest and the primary source of diversity to several Neotropical regions. The origins of such diversity continue to be an unresolved question in evolutionary biology. Among many competing hypotheses to explain the evolution of the Amazonian biodiversity, one stands out as the most influential: the refugia hypothesis by Jürgen Haffer. Here, we provide a chronological overview on how the refugia hypothesis evolved over the decades and how the criticism from different fields affected its acceptance. We conclude that the refugia hypothesis alone cannot explain the diversification of the complex Amazonian diversity, and perhaps it was not the most important diversification mechanism. However, the debate provoked by refugia has produced a great amount of knowledge on Amazonian climatic, geological, and evolutionary processes, as well as on species distributions, movements, and history.
The habitat functional response links seasonal third‐order selection to second‐order landscape characteristics
Authors: Paolini Kelsey E. , Strickland Bronson K. , Tegt Jessica L. , VerCauteren Kurt C. , Street Garrett M.
Published: March 2019

Determining how animals respond to differences in resource availabilities across spatiotemporal extents is critical to our understanding of organism distributions. Variations in resource distribution leading to changes in spatial arrangements across landscapes are indicative of a habitat functional response. Our goal was to assess how resource availabilities influenced both second‐order (i.e., home ranging behavior) and third‐order (i.e., habitat or resource selection) selection by feral pigs (Sus scrofa) in an agricultural landscape. We defined agriculturally based seasons to estimate home range characteristics using autocorrelated kernel density estimation within each season. We then modeled home range size as a function of resource availability (i.e., resource selection analyses) to determine whether individual behaviors were predicted by shifts in home ranging behavior. Both home range analyses and resource selection analyses indicated seasonal differences in selection for agricultural resources as availabilities changed, suggesting second‐ and third‐order selection is mechanistically linked through a habitat functional response.
Is dietary or microhabitat specialization associated with environmental heterogeneity in horned lizards (Phrynosoma)?
Authors: Refsnider Jeanine M. , Carter Sarah E. , Kramer Gunnar R. , Siefker Adam D. , Streby Henry M.
Published: March 2019

Niche breadth is predicted to correlate with environmental heterogeneity, such that generalists will evolve in heterogeneous environments and specialists will evolve in environments that vary less over space and time. We tested the hypothesis that lizards in a heterogeneous environment were generalists compared to lizards in a homogeneous environment. We compared niche breadths of greater short‐horned lizards by quantifying resource selection in terms of two different niche axes, diet (prey items and trophic level), and microhabitat (ground cover and shade cover) between two populations occurring at different elevations. We assessed the heterogeneity of dietary and microhabitat resources within each population's environment by quantifying the availability of prey items, ground cover, and shade cover in each environment. Overall, our results demonstrate that despite differences in resource heterogeneity between elevations, resource selection did not consistently differ between populations. Moreover, environmental heterogeneity was not associated with generalization of resource use. The low‐elevation site had a broader range of available prey items, yet lizards at the high‐elevation site demonstrated more generalization in diet. In contrast, the high‐elevation site had a broader range of available microhabitats, but the lizard populations at both sites were similarly generalized for shade cover selection and were similarly specialized for ground cover selection. Our results demonstrate that environmental heterogeneity of a particular resource does not necessarily predict the degree to which organisms specialize on that resource.