bluuebunny/crossref_metadata_2025 huggingface dataset:
Bullen's Parameter as a Seismic Observable for Spin Crossovers in the Lower Mantle
Authors: Valencia‐Cardona Juan J. , Williams Quentin , Shukla Gaurav , Wentzcovitch Renata M.
Published: September 2017

Elastic anomalies produced by the spin crossover in ferropericlase have been documented by both first‐principles calculations and high pressure‐temperature experiments. The predicted signature of this spin crossover in the lower mantle is, however, subtle and difficult to geophysically observe within the mantle. Indeed, global seismic anomalies associated with spin transitions have not yet been recognized in seismologic studies of the deep mantle. A sensitive seismic parameter is needed to determine the presence and amplitude of such a spin crossover signature. The effects of spin crossovers on Bullen's parameter, η, are assessed here for a range of compositions, thermal profiles, and lateral variations in temperature within the lower mantle. Velocity anomalies associated with the spin crossover in ferropericlase span a depth range near 1,000 km for typical mantle temperatures. Positive excursions of Bullen's parameter with a maximum amplitude of ∼0.03 are calculated to be present over a broad depth range within the middle‐to‐deep lower mantle: these are largest for peridotitic and harzburgitic compositions. These excursions are highest in amplitude for model lower mantles with large lateral thermal variations and with cold downwellings having longer lateral length‐scales relative to hot upwellings. We conclude that predicted deviations in Bullen's parameter due to the spin crossover in ferropericlase for geophysically relevant compositions may be sufficiently large to resolve in accurate seismic inversions of this parameter and could shed light on both the lateral variations in temperature at depth within the lower mantle, and the amount of ferropericlase at depth.
Multiple‐Satellite Observation of Magnetic Dip Event During the Substorm on 10 October 2013
Authors: He Zhaoguo , Chen Lunjin , Zhu Hui , Xia Zhiyang , Reeves G. D. , Xiong Ying , Xie Lun , Cao Yong
Published: September 2017

We present a multiple‐satellite observation of the magnetic dip event during the substorm on 10 October 2013. The observation illustrates the temporal and spatial evolution of the magnetic dip and gives a compelling evidence that ring current ions induce the magnetic dip by enhanced plasma beta. The dip moves with the energetic ions in a comparable drift velocity and affects the dynamics of relativistic electrons in the radiation belt. In addition, the magnetic dip provides a favorable condition for the electromagnetic ion cyclotron (EMIC) wave generation based on the linear theory analysis. The calculated proton diffusion coefficients show that the observed EMIC wave can lead to the pitch angle scattering losses of the ring current ions, which in turn partially relax the magnetic dip in the observations. This study enriches our understanding of magnetic dip evolution and demonstrates the important role of the magnetic dip for the coupling of radiation belt and ring current.
Significant Aerosol Influence on the Recent Decadal Decrease in Tropical Cyclone Activity Over the Western North Pacific
Authors: Takahashi Chiharu , Watanabe Masahiro , Mori Masato
Published: September 2017

Over the past two decades, the number of tropical cyclones (TCs) has decreased markedly in the southeastern part of the western North Pacific (WNP) as a component of the interdecadal variation. This decrease has partially been explained by an internal low‐frequency variability of sea surface temperature (SST) in the Pacific, but influences of external forcing remain unclear. Here we show that past changes in sulfate aerosol emissions contributed approximately 60% of the observed decreasing trends in TC genesis frequency in the southeastern WNP for 1992–2011, using multiple simulations by a global climate model. This decrease was mainly attributed to the increased vertical wind shear and decreased low‐level vorticity, associated with a trans‐basin multidecadal SST change driven by aerosol forcing. The near‐future projection shows that the aerosol forcing still has some potential influence on decadal TC change, but the projected decreasing frequency is mainly due to increasing greenhouse gases forcing.
Joint Inversion of Surface Wave Dispersions and Receiver Functions with P Velocity Constraints: Application to Southeastern Tibet
Authors: Li Jiangtao , Song Xiaodong , Zhu Lupei , Deng Yangfan
Published: September 2017

We introduced a P velocity model into the traditional joint inversion of P receiver function (RF) and surface wave dispersions to reduce model ambiguity. The method was implemented using a global search‐based algorithm and a flexible parameterization of a sedimentary layer and spline‐based parameterization that can represent sharp discontinuities. We applied the method to a dense array in SE Tibet (longitude ~97.5°E to 107°E, latitude ~25.3°N). Extensive tests using synthetic and real data suggest that the method is suitable and robust for a variety of velocity structures and Moho discontinuities and can simultaneously provide the crustal Vp/Vs profile and better constrained Moho depth. The flexibility of the parameterization and the inclusion of the Vp constraint are crucial in the improved model recovery. Artifacts may be created without including the sedimentary layer. Even when it is less perfect, a reasonable Vp model is valuable in such a joint inversion. We showed that crustal multiples in RFs may bias the traditional H‐k results when the crust structure is complex and should be avoided in a joint inversion before appropriate corrections can be made. The results from the joint inversion show two low‐velocity zones (LVZs) reported previously and were identified as channels of crustal flow. A prominent isolated LVZ is observed in the mid‐lower crust under the Xiaojiang fault area, which correlates with anomalously high Vp/Vs ratios, indicating possible partial melting. However, the other LVZ is imaged to be in the brittle shallow upper crust without very high Vp/Vs ratios, which is likely associated with crustal fault zones rather than partial melting. We observe clear low‐velocity structures in the mantle beneath the two crustal LVZs, which also correlate with zones of low resistivity. The crust‐mantle correlation may suggest influence of mantle processes on crustal deformation.
Uniting Strength and Toughness of Al Matrix Composites with Coordinated Al3Ni and Al3Ti Reinforcements
Authors: Heim Frederick M. , Zhang Yunya , Li Xiaodong
Published: September 2017

Hybrid aluminum composites are fabricated in a novel manner to characteristically induce a layer‐wise aligned distribution of micro‐scale Al3Ni and Al3Ti intermetallic particles that are formed in situ within a ductile Al matrix. The simple and unique Rolling of Randomly Orientated Layer‐wise Materials (RROLM) manufacturing methodology enables microstructural tailoring of the intermetallic reinforcing particles to prescribe enhanced crack tip deflection caused by the complex interaction of local veins of reinforcement particles, in an effort to overshadow the classical loss of toughness in large‐particle reinforced composites. The complimentary reinforcements and their interface with the Al matrix are revealed to have a gradual transition zone that functions to maintain critical cohesion with the particles and the matrix, empowering the superior load transfer capability of the particles, and reducing microvoid penetration into the matrix. In situ three‐point bending observations combined with a local strain field analysis, demonstrate the distinctive crack deflection mechanisms exhibit by the composite. Deviating from the norm, this specialized particle reinforced composite exhibited both strengthening and toughening mechanisms simultaneously, over control samples. The investigated design strategy and model material will assist materials development toward light‐weight, stronger, and tougher particle reinforced Al matrix composites.
Intracellular Pathways Involved in Bone Regeneration Triggered by Recombinant Silk–Silica Chimeras
Authors: Martín‐Moldes Zaira , Ebrahimi Davoud , Plowright Robyn , Dinjaski Nina , Perry Carole C. , Buehler Markus J. , Kaplan David L.
Published: September 2017

Biomineralization at the organic–inorganic interface is critical to many biology material functions in vitro and in vivo. Recombinant silk–silica fusion peptides are organic–inorganic hybrid material systems that can be effectively used to study and control biologically mediated mineralization due to the genetic basis of sequence control. However, to date, the mechanisms by which these functionalized silk–silica proteins trigger the differentiation of human mesenchymal stem cells (hMSCs) to osteoblasts remain unknown. To address this challenge, silk–silica surfaces are analyzed for silica–hMSC receptor binding and activation, and the intracellular pathways involved in the induction of osteogenesis on these bioengineered biomaterials. The induction of gene expression of αVβ3 integrin, all three mitogen‐activated protein kinsases, as well as c‐Jun, runt‐related transcription factor 2, and osteoblast marker genes is demonstrated upon growth of the hMSCs on the silk–silica materials. This induction of key markers of osteogenesis correlates with the content of silica on the materials. Moreover, computational simulations are performed for silk/silica‐integrin binding which show activation of αVβ3 integrin in contact with silica. This integrated computational and experimental approach provides insight into interactions that regulate osteogenesis toward more efficient biomaterial designs.
Development of a Dual‐Modally Traceable Nanoplatform for Cancer Theranostics Using Natural Circulating Cell‐Derived Microparticles in Oral Cancer Patients
Authors: Yu Zi‐Li , Zhang Wei , Zhao Jing‐Ya , Zhong Wen‐Qun , Ren Jian‐Gang , Wu Min , Zhang Zhi‐Ling , Pang Dai‐Wen , Zhao Yi‐Fang , Chen Gang
Published: September 2017

Cell‐derived microparticles (MPs), which are biogenic nanosized membrane vesicles that convey bioactive molecules between cells, have exhibited great potential to serve as therapeutic platforms. However, so far, all the MPs used as theranostic vectors in previous studies have been produced in vitro from cell culture supernatants, which is still associated with several concerns regarding practical applications. In this study, circulating MPs (CMPs), which are freshly purified from the peripheral blood of oral squamous cell carcinoma (OSCC) patients, are directly and efficiently embedded with ultrasmall near‐infrared‐fluorescent magnetic quantum dots (Ag2Se@Mn QDs) via electroporation. By virtue of the superior photostability, favorable biocompatibility, and dual‐mode traceability of Ag2Se@Mn QD‐labeled CMPs in vivo, the tissue distribution and natural tumor‐targeting behavior of CMPs from OSCC patients are directly visualized in living mice for the first time. Moreover, by simultaneously embedding antitumor siRNA and Ag2Se@Mn QDs into CMPs derived from OSCC patients, a dual‐modally traceable and actively tumor‐targeted nanoplatform for cancer theranostics is developed. This study reports the first reliable conjugation‐free labeling strategy for in vivo dual‐mode tracking of CMPs harvested from the human body, and, more importantly, reports the development of traceable tumor‐targeted theranostic vectors based on naturally occurring CMPs from cancer patients.
From Ionogels to Biredox Ionic Liquids: Some Emerging Opportunities for Electrochemical Energy Storage and Conversion Devices
Authors: Vioux André , Coasne Benoit
Published: September 2017

Ionic liquids (ILs) continue to receive attention for applications in electrochemistry because of their unique properties as charge carriers (electrolytes) and redox shuttles (solar cells) and their ability to promote energy storage either electrostatically (supercapacitors) or chemically (secondary batteries). More specifically, the confinement of ILs in nanopores or the adsorption at surfaces, are considered a promising strategy for all solid‐state energy storage and conversion devices. Upon such immobilization, one benefits from the specific properties of ILs (large electrochemical window, relatively high ionic conductivity, task‐specific functionalities, etc.) combined with surface and confinement effects that can be tuned by playing with the porosity and chemical nature of the host. Here, some emerging applications of ILs in electrochemistry are first discussed: silica‐based ionogels as solid electrolytes and systems that involve carbon host substrates, as typical electrode materials in electrical double layer capacitors and lithium secondary batteries. Also, a non‐exhaustive, yet a comprehensive picture of the confinement and surface effects at play in such applications is presented. Then, the confinement of task‐specific ILs such as protonic ILs, IL lithium salts, and biredox ILs, is discussed, which paves the way for promising perspectives. Finally, some concluding remarks are reported and directions for future work are suggested.
Factors underlying observed injury rate differences between temporary workers and permanent peers
Authors: Foley Michael
Published: September 2017

Background

Temporary workers face increased risk of injury as compared to permanent workers in similar occupations. This study explores the role played by several potential risk factors.

Methods

Injured temporary and permanent workers, matched by industry, tenure and demographic characteristics, were interviewed to isolate the association of temporary employment with several injury risk factors.

Results

Temporary workers had higher workers’ compensation claims rates than their permanent worker‐peers. In interviews temporary workers a reported a lower frequency of exposure to hazards. However, they also reported being less likely to be equipped to cope with hazards by such countermeasures as experience screening, safety training and task control.

Conclusion

Policies are needed to improve screening and training of temporary workers to assigned tasks, to discourage job‐switching, to improve temporary workers’ hazard awareness, to protect their right to report unsafe conditions. The responsibilities of agencies and host employers for ensuring the safety of their temporary workers need clarification in regulatory policy.
The Arbitration from Hell and How the New York Courts Got It Wrong
Authors: Solovay Norman
Published: September 2017

This article follows‐up on the author's reporting, which explained why the New York state's Appellate Division, First Department, was wrong in 2012 when it unanimously upheld a New York lower court's vacatur of an arbitrator's sanctions award against Jack J. Grynberg in Matter of Jack J. Grynberg et al., Respondents, v. BP Exploration Operating Co. Ltd. et al., Appellants, 92 A.D.3d 547, 938 N.Y.S.2d 439 (2012) (available at http://bit.ly/2x7FXpj).
Explaining the Obvious: How Appraisals, Health Care, and More Implement ADR in the Insurance Field
Authors: Jerry Robert H.
Published: September 2017

In Part 1 in the July/August Alternatives, Prof. Robert H. Jerry II began an overview of the current state of the use of alternative dispute resolution practices in the U.S. insurance industry by focusing extensively on mass disaster claims. This month, he returns with the second of two parts to comment on claims processing in automobile and homeowners' and in health insurance, as well as the health care industry more generally.
No Surprise Party for Us! Here's What Happens When the Unexpected Arises at the Mediation Table
Authors: Creo Robert A.
Published: September 2017

So, at the transactional table of a mediation session, mediators strive to create a safe environment where counsel and parties feel safe to be open and candid. Here, surprise is not a tactic and is reframed as disclosure and good‐faith communication.
Alcohol improves cerebellar learning deficit in myoclonus–dystonia: A clinical and electrophysiological investigation
Authors: Weissbach Anne , Werner Elisa , Bally Julien F. , Tunc Sinem , Löns Sebastian , Timmann Dagmar , Zeuner Kirsten E. , Tadic Vera , Brüggemann Norbert , Lang Anthony , Klein Christine , Münchau Alexander , Bäumer Tobias
Published: September 2017

Objective

To characterize neurophysiological subcortical abnormalities in myoclonus–dystonia and their modulation by alcohol administration.

Methods

Cerebellar associative learning and basal ganglia–brainstem interaction were investigated in 17 myoclonus–dystonia patients with epsilon‐sarcoglycan (SGCE) gene mutation and 21 age‐ and sex‐matched healthy controls by means of classical eyeblink conditioning and blink reflex recovery cycle before and after alcohol intake resulting in a breath alcohol concentration of 0.08% (0.8g/l). The alcohol responsiveness of clinical symptoms was evaluated by 3 blinded raters with a standardized video protocol and clinical rating scales including the Unified Myoclonus Rating Scale and the Burke–Fahn–Marsden Dystonia Rating Scale.

Results

Patients showed a significantly reduced number of conditioned eyeblink responses before alcohol administration compared to controls. Whereas the conditioning response rate decreased under alcohol intake in controls, it increased in patients (analysis of variance: alcohol state × group, p = 0.004). Blink reflex recovery cycle before and after alcohol intake did not differ between groups. Myoclonus improved significantly after alcohol intake (p = 0.016). The severity of action myoclonus at baseline correlated negatively with the conditioning response in classical eyeblink conditioning in patients.

Interpretation

The combination of findings of reduced baseline acquisition of conditioned eyeblink responses and normal blink reflex recovery cycle in patients who improved significantly with alcohol intake suggests a crucial role of cerebellar networks in the generation of symptoms in these patients. Ann Neurol 2017;82:543–553
Structuring of Surfaces with Gold Nanoparticles by Using Bessel‐Like Beams
Authors: Stankevičius Evaldas , Garliauskas Mantas , Gedvilas Mindaugas , Tarasenko Nikolai , Račiukaitis Gediminas
Published: September 2017

Here, the structuring of surfaces with gold nanoparticles by using Bessel‐like beam array is demonstrated. The experimental results show that the fabricated microring structures containing gold nanoparticles have a surface plasmon resonance in the spectral range of 520–540 nm, which can be tuned by selecting the laser treatment parameters. Fabricated microring structures exhibit a lower light transmittance comparing with the randomly distributed gold nanoparticles for wavelengths 500–570 nm due to the growth in the size of nanoparticles. In the spectral range of 600–700 nm, the light transmittance through microring structures is higher compared with the randomly distributed gold nanoparticles because of the removal of gold nanoparticles as gold has high reflectivity for wavelengths longer than 600 nm. The demonstrated method enables an easy fabrication of microring structures having tunable plasmonic properties.
Black Pigment Gallstone Inspired Platinum‐Chelated Bilirubin Nanoparticles for Combined Photoacoustic Imaging and Photothermal Therapy of Cancers
Authors: Lee Dong Yun , Kim Jin Yong , Lee Yonghyun , Lee Soyoung , Miao Wenjun , Kim Hyeon Sik , Min Jung‐Joon , Jon Sangyong
Published: September 2017

Bilirubin (BR), a bile pigment that exerts potent antioxidant and anti‐inflammatory effects, is also a major constituent of black pigment gallstones found in bile ducts under certain pathological conditions. Inspired by the intrinsic metal‐chelating power of BR found in gallstones, herein we report a cisplatin‐chelated BR‐based nanoparticle (cisPt@BRNP) for use as a new photonic nanomedicine for combined photoacoustic imaging and photothermal therapy of cancers. The cisPt@BRNPs were prepared by simply mixing cisplatin with BRNPs, yielding ca. 150‐nm‐size NPs. Upon near‐IR laser irradiation at 808 nm, cisPt@BRNPs generated considerable heat and induced clear death of cancer cells in vitro. Following intravenous injection into human colon cancer‐bearing mice, cisPt@BRNPs allowed effective tumor visualization by photoacoustic imaging and remarkable antitumor efficacy by photothermal therapy, suggesting their potential for use as a new photonic nanomedicine for cancer therapy.
A Multiple‐Stimulus‐Responsive Biomimetic Assembly Based on a Polyisocyanopeptide and Conjugated Polymer
Authors: Meng Fanfan , Xing Chengfen , Yuan Hongbo , Fan Yibing , Chai Ran , Zhan Yong
Published: September 2017

An assembly was fabricated and was revealed to be a multiple‐stimulus‐responsive biomimetic hybrid polymer architecture. It was constructed by the hydrophobic interactions between a conjugated polyfluorene that contained 2,1,3‐benzothiadiazole units (PFBT) and a tri(ethylene glycol)‐functionalized polyisocyanopeptide (3OEG‐PIC). The introduction of PFBT to the polyisocyanopeptide (PIC) network allowed for the incorporation of responsiveness to multiple stimuli including temperature, CO2, carbonic anhydrase, and nonlinear mechanics, which mimics natural processes and interactions. Furthermore, the light‐harvesting and signal amplification characteristics of PFBT endowed the supramolecular assembly with the essential function of fluorescence monitoring for biological processes.
The Oxidation of Hydrophobic Aromatic Substrates by Using a Variant of the P450 Monooxygenase CYP101B1
Authors: Sarkar Md. Raihan , Lee Joel H. Z. , Bell Stephen G.
Published: September 2017

The cytochrome P450 monooxygenase CYP101B1, from a Novosphingobium bacterium is able to bind and oxidise aromatic substrates but at a lower activity and efficiency than norisoprenoids and monoterpenoid esters. Histidine 85 of CYP101B1 aligns with tyrosine 96 of CYP101A1, which, in the latter enzyme forms the only hydrophilic interaction with its substrate, camphor. The histidine residue of CYP101B1 was mutated to phenylalanine with the aim of improving the activity of the enzyme for hydrophobic substrates. The H85F mutant lowered the binding affinity and activity of the enzyme for β‐ionone and altered the oxidation selectivity. This variant also showed enhanced affinity and activity towards alkylbenzenes, styrenes and methylnaphthalenes. For example the rate of product formation for acenaphthene oxidation was improved sixfold to 245 nmol per nmol CYP per min. Certain disubstituted naphthalenes and substrates, such as phenylcyclohexane and biphenyls, were oxidised with lower activity by the H85F variant. Variants at H85 (A and G) designed to introduce additional space into the active site so as to accommodate these larger substrates did not improve the oxidation activity. As the H85F mutant of CYP101B1 improved the oxidation of hydrophobic substrates, this residue is likely to be in the substrate binding pocket or the access channel of the enzyme. The side chain of the histidine might interact with the carbonyl groups of the favoured norisoprenoid substrates of CYP101B1.
Setting the Stage: Broadly Considering Gender Constructions
Authors: Lester Jaime , Klein Carrie
Published: September 2017

This chapter provides a portrait of the overrepresentation of women in community colleges and introduces contemporary research on men and masculinity to argue the need for more inclusive conceptualizations of gender issues.
The Clery Act on Campus: Status Update and Gender Implications
Authors: Lee E. Ashleigh Schuller
Published: September 2017

This chapter provides a summary of the history of the Clery Act and reviews the latest developments of the Violence Against Women Reauthorization Act. In light of this legislation, campus collaboration should occur to ensure students’ safety and institutional legal compliance regarding mandatory reporting requirements.
Facile Structure Tuning of a Methanol‐Synthesis Catalyst towards the Direct Synthesis of Dimethyl Ether from Syngas
Authors: Jeong Cheonwoo , Ham Hyungwon , Bae Jong Wook , Kang Dong‐Chang , Shin Chae‐Ho , Baik Joon Hyun , Suh Young‐Woong
Published: September 2017

Heterogeneous catalysts of bifunctionality offer improved process efficiency and enhanced product yield in multistep chemical transformations conducted in a consecutive manner. However, this has seldom been realized in coprecipitated catalysts owing to the complexity of the synthesis. By adjusting the synthesis protocol of an industrial methanol‐synthesis catalyst as a model system, herein we demonstrate the bifunctional effect of Al2O3/Cu/ZnO catalysts to enable the direct production of dimethyl ether from synthesis gas with yields that are 2–3‐fold higher than those obtained with their conventional counterparts, with a greater number of accessible Cu surface atoms and more Al2O3 acid sites existing at the external particle surface. This is achieved by preparing the fully developed Cu,Zn precursor of a specific structure with surface‐decorated Al species. Our approach paves the way towards the rational design of multicomponent precipitated catalysts with tunable bifunctionality for practical cascade reactions.
Modulation of Nitrile Hydratase Regioselectivity towards Dinitriles by Tailoring the Substrate Binding Pocket Residues
Authors: Cheng Zhongyi , Cui Wenjing , Xia Yuanyuan , Peplowski Lukasz , Kobayashi Michihiko , Zhou Zhemin
Published: September 2017

The regioselective hydration of dinitriles is one of the most attractive approaches to prepare ω‐cyanocarboxamides or diamides and such regioselectivity is often beyond the capability of chemical catalysts. The use of nitrile hydratase to biotransform dinitriles selectively would be highly desirable. Molecular docking of two aliphatic dinitriles and two aromatic dinitriles into the active site of a nitrile hydratase (NHase) from Rhodococcus rhodochrous J1 allowed the identification of proximal NHase substrate binding pocket residues. Four residues (βLeu48, βPhe51, βTyr68, and βTrp72) were selected for single‐ and double‐point mutations to modulate the NHase regioselectivity towards dinitriles. Several NHase mutants with an altered regioselectivity were obtained, and the best one was Y68T/W72Y. Docking experiments further indicated that the poor binding affinity of aliphatic and aromatic ω‐cyanocarboxamides to the NHase variants resulted in distinct regioselectivity between wild‐type and mutated NHases.
Tungsten‐Based Bimetallic Catalysts for Selective Cleavage of Lignin C−O Bonds
Authors: Ji Jianwei , Guo Haiwei , Li Changzhi , Qi Zaojuan , Zhang Bo , Dai Tao , Jiang Min , Ren Chuanqing , Wang Aiqin , Zhang Tao
Published: September 2017

Tungsten‐based bimetallic catalysts M–W/AC (M=Ru, Pt, and Pd; AC=activated carbon) exhibited high activity and selectivity in the hydrogenolysis of typical α‐O‐4 model compounds and deconstruction of lignin feedstock for the production of aromatic chemicals. Synergy effect was observed between tungsten and noble‐metal species, which on the one hand modulated the hydrogenolysis activity of tungsten and improved the activity of catalyst, and on the other hand suppressed overhydrogenation that avoided the formation of cycloalkanes. The conversion of α‐O‐4 model compounds with different substituents showed that electronic effects play an important role in stabilizing the reaction intermediates, and the electron‐donating methoxy group on the aromatic ring accelerated the hydrogenolysis efficiency. Solvent effect was another factor that determined hydrogenolysis efficiency; dipolar aprotic solvents such as n‐hexane provided the high yields of target aromatics. In the conversion of realistic lignins, the bimetallic catalyst showed excellent activity not only in α‐O‐4 cleavage but also in the hydrogenolysis of other major linkages such as β‐O‐4 and β−β between aromatic units, so that a high yield of liquid oil was obtained from lignin.
Catalytic Asymmetric Huisgen Alkyne–Azide Cycloaddition of Bisalkynes by Copper(I) Nanoparticles
Authors: Chen Mu‐Yi , Xu Zheng , Chen Li , Song Tao , Zheng Zhan‐Jiang , Cao Jian , Cui Yu‐Ming , Xu Li‐Wen
Published: September 2017

The use of chiral ligands to tune the reactivity and enantioselectivity of transition‐metal catalyst for asymmetric transformations is a central challenge in synthetic organic chemistry. In this manuscript, chiral P‐ligand (Tao‐Phos)‐assisted Cu2O‐nanoparticles‐catalyzed asymmetric azide–alkyne Huisgen cycloaddition is reported. The unique features of Tao‐Phos were determined in the copper‐catalyzed desymmetrization of pyrazolone‐derived bisalkynes through catalytic asymmetric Huisgen [3+2] cycloaddition (CAHC). This CAHC transformation resulted in good yields with moderate to high enantioselectivities.
Coupling and Dearomatization of Pyridines at a Transient η2‐Cyclopropene/Bicyclobutane Zirconocene Complex
Authors: Romero Nuria , Dufrois Quentin , Vendier Laure , Dinoi Chiara , Etienne Michel
Published: September 2017

This paper reports on stereospecific coupling reactions between an η2‐cyclopropene ligand and pyridine derivatives, which are preferred to alternative C−H bond activation reactions. The dicyclopropylzirconocene complex [Cp2Zr(c‐C3H5)2] (1) eliminates cyclopropane to generate the η2‐cyclopropene/bicyclobutane intermediate [Cp2Zr(η2‐c‐C3H4)] (A). A does not activate any pyridine C−H bonds, but rather pyridine inserts into a Zr−C bond of A, yielding an azazirconacycle with a dearomatized pyridyl group [Cp2Zr{κ2‐N,C8‐(2‐c‐C3H4)‐C5H5N}] (2). Kinetic data, isotopelabelling experiments, and DFT calculations indicate that the rate‐determining step of this stereospecific reaction is cyclopropane elimination, and that the stability of the intermediate [Cp2Zr(η2‐c‐C3H4)(NC5H5)] (A‐py) governs the selectivity of the reaction. Complex 2 tautomerizes to [Cp2Zr{κ2‐N,C8‐(2‐C3H5)‐C5H4N}] (6) through a base‐catalyzed proton migration accompanied by cyclopropyl opening and restoration of conjugation within the zirconacycle.
Strategy for Stereoselective Metal‐free α‐Functionalization of 2‐Azaaryl Acetates with N‐Boc Imines
Authors: Bastida Iñaki , Segundo Marcos San , López Rosa , Palomo Claudio
Published: September 2017

We report the first diastereo‐ and enantioselective formal Mannich reaction of 2‐pyridyl acetates which gives rise to α‐ and β‐functionalized 2‐substituted pyridines. Key for success is the previous azaarene N‐oxide formation enabling α‐carbon deprotonation by a mild bifunctional Brønsted base and subsequent reaction with N‐Boc imines under almost perfect stereocontrol.
Flow Enhancement of Shear‐Thinning Liquids in Capillaries Subjected to Longitudinal Vibrations
Authors: Ellenberger Jürg , Krishna Rajamani
Published: September 2017

Application of sinusoidal vibrations in the longitudinal direction causes a significant enhancement in the flow rate of shear‐thinning carboxymethylcellulose and polyacrylamide solutions inside capillaries. Depending on the vibration frequency and amplitude, flow enhancements of up to a factor of 9.6 have been realized. Video imaging of a tracer particle inside the tube provides insights into the liquid motion. In particular, it should be noted that the phase shift between the sinusoidal motion of the tube wall and the liquid inside the tube is of high importance in determining the flow enhancement factor.
Titania‐Supported Single‐Atom Platinum Catalyst for Water‐Gas Shift Reaction
Authors: Ammal Salai Cheettu , Heyden Andreas
Published: September 2017

Density functional theory (DFT) and microkinetic modeling are used to examine the water‐gas shift (WGS) reaction on TiO2(110)‐supported single Pt atoms. A CO‐adsorbed Pt atom supported on a TiO2 surface exhibits a lower activity for the WGS than the Pt2+ ion supported on a doped TiO2 surface, although DFT predicts the CO‐adsorbed Pt on an undoped TiO2 surface to be thermodynamically more stable. Trends observed in WGS activity for different active sites of TiO2‐supported Pt catalysts can be explained in terms of CO adsorption strength and the ability to form an oxygen vacancy on the oxide support.
Basic Properties of Nd‐Doped GYSGG Laser Crystal
Authors: Ding Shoujun , Zhang Qingli , Luo Jianqiao , Liu Wenpeng , Sun Dunlu , Wang Xiaofei , Sun Guihua , Gao Jinyun
Published: September 2017

In the present work, we investigated the mechanical properties (including hardness, fracture toughness, brittleness index and yield strength) of Nd0.03Gd0.93Y2.04Sc2Ga3O12 (Nd:GYSGG) laser crystal using Vickers microhardness tester, for the first time. The defects morphology of Nd:GYSGG crystal were investigated by using chemical etching method with phosphoric acid etchant. The absorption spectrum of Nd:GYSGG from 300 to 2800 nm was measured at room temperature and the absorption peaks were assigned. The fluorescence lifetime of the 4F3/2→4I11/2 transition of Nd3+ in GYSGG is fitted to be 221.3 μs. The three Judd‐Ofelt intense parameters Ω2, 4, 6 were calculated to be 0.329 × 10−20 cm2, 2.761 × 10−20 cm2 and 4.222 × 10−20 cm2, respectively. All these demonstrate that Nd:GYSGG crystal is a good candidate laser material.
Effect of Formamidinium/Cesium Substitution and PbI2 on the Long‐Term Stability of Triple‐Cation Perovskites
Authors: Shukla Shashwat , Shukla Sudhanshu , Haur Lew Jia , Dintakurti Sai S. H. , Han Guifang , Priyadarshi Anish , Baikie Tom , Mhaisalkar Subodh G. , Mathews Nripan
Published: September 2017

Altering cation and anion ratios in perovskites has proven an excellent means of tuning the perovskite properties and enhancing the performance. Recently, methylammonium/formamidinium/cesium triple‐cation mixed‐halide perovskites have demonstrated efficiencies up to 22 %. Similar to the widely explored methylammonium lead halide, excess PbI2 is added to these perovskite films to enhance their performances. The excess PbI2 is known to be beneficial for the performance. However, its impact on stability is less well known. Triple‐cation perovskites deploy excess PbI2 up to 8 %. Thus, it is imperative to analyze the role of excess PbI2 in the degradation kinetics. In this study, the amount of PbI2 in the triple‐cation perovskite films is varied and the degradation kinetics monitored by X‐ray diffraction and optical absorption spectroscopy. The inclusion of excess PbI2 is shown to adversely affect the stability of the material. Faster degradation kinetics are observed for samples with higher PbI2 contents. However, samples with excess PbI2 also showed superior properties such as enhanced grain sizes and better optical absorption. Thus, careful management of the PbI2 quantity is required to obtain better stability and alternative pathways should be explored to achieve better device performance rather than adding excess PbI2.
Cascade Reductive Etherification of Bioderived Aldehydes over Zr‐Based Catalysts
Authors: Shinde Suhas , Rode Chandrashekhar
Published: September 2017

An efficient one‐pot catalytic cascade sequence has been developed for the production of value‐added ethers from bioderived aldehydes. Etherification of 5‐(hydroxymethyl)furfural with different aliphatic alcohols over acidic Zr–montmorillonite (Zr‐Mont) catalyst produced a mixture of 5‐(alkoxymethyl)furfural and 2‐(dialkoxymethyl)‐5‐(alkoxymethyl)furan. The latter was selectively converted back into 5‐(alkoxymethyl)furfural by treating it with water over the same catalyst. The synthesis of 2,5‐bis(alkoxymethyl)furan was achieved through a cascade sequence involving etherification, transfer hydrogenation, and re‐etherification over a combination of acidic Zr‐Mont and the charge‐transfer hydrogenation catalyst [ZrO(OH)2]. This catalyst combination was further explored for the cascade conversion of 2‐furfuraldehyde into 2‐(alkoxymethyl)furan. The scope of this strategy was then extended for the reductive etherification of lignin‐derived arylaldehydes to obtain the respective benzyl ethers in >80 % yield. Additionally, the mixture of Zr‐Mont and ZrO(OH)2 does not undergo mutual destruction, which was proved by recycling experiments and XRD analysis. Both the catalysts were thoroughly characterized using BET, temperature‐programmed desorption of NH3 and CO2, pyridine‐FTIR, XRD, inductively coupled plasma optical emission spectroscopy, and X‐ray photoelectron spectroscopy techniques.
Biocatalytic Valorization of Furans: Opportunities for Inherently Unstable Substrates
Authors: Domínguez de María Pablo , Guajardo Nadia
Published: September 2017

Biogenic furans (furfural and 5‐hydroxymethylfurfural) are expected to become relevant building blocks based on their high degree of functionality and versatility. However, the inherent instability of furans poses considerable challenges for their synthetic modifications. Valorization routes of furans typically generate byproducts, impurities, wastes, and a cumbersome downstream processing, compromising their ecological footprint. Biocatalysis may become an alternative, given the high selectivity of enzymes, together with the mild reaction conditions applied. This Review critically discusses the options for enzymes in the upgrading of furans. Based on previous reports, a variety of biocatalytic transformations have been applied to furans, with successful cases both in aqueous and in water‐free media. Options comprise the biodetoxification of toxic furans in hydrolysates, selective syntheses based on oxidation–reduction processes, solvent‐free esterifications, or carboligations to afford C12 derivatives. Reported strategies show in general promising but still modest productivities (2–30 gproduct L−1 d−1, depending on the example). There are opportunities with high potential and deserving of further development, scale‐up, and technoeconomic assessment, to entirely validate them as realistic alternatives.
Ultra‐Low Doses of Naltrexone Enhance the Antiallodynic Effect of Pregabalin or Gabapentin in Neuropathic Rats
Authors: Pineda‐Farias Jorge B. , Caram‐Salas Nadia L. , Salinas‐Abarca Ana B. , Ocampo Jorge , Granados‐Soto Vinicio
Published: September 2017

Preclinical Research

Treatment of neuropathic pain is an area of largely unmet medical need. Pregabalin and gabapentin are anticonvulsants widely used for the treatment of neuropathic pain. Unfortunately, these drugs are only effective in 50–60% of the treated patients. In addition, both drugs have substantial side effects. Several studies have reported that ultralow doses of opioid receptor antagonists can induce analgesia and enhance the analgesic effect of opioids in rodents and humans. The objective of the present study was to assess the antiallodynic synergistic interaction between gabapentinoids and naltrexone in rats. Oral administration of pregabalin (ED50 = 2.79 ± 0.16 mg/kg) or gabapentin (ED50 = 21.04 ± 2.87 mg/kg) as well as intrathecal naltrexone (ED50 = 0.11 ± 0.02 ng) reduced in a dose‐dependent manner tactile allodynia in rats. Maximal antiallodynic effects (∼100%) were reached with 30 mg/kg of pregabalin, 300 mg/kg of gabapentin or 0.5 ng of naltrexone. Co‐administration of pregabalin or gabapentin and naltrexone in a fixed‐dose ratio (1:1) remarkably reduced spinal nerve ligation‐induced tactile allodynia showing a synergistic interaction. The data indicate that combinations of pregabalin or gabapentin and ultra‐low doses of naltrexone are able to reduce tactile allodynia in neuropathic rats with lower doses that those used when drugs are given individually and with an improved side effects profile. Drug Dev Res 78 : 371‐380, 2017. © 2017 Wiley Periodicals, Inc.
Disentangling shallow‐water bulk carbonate carbon isotope archives with evidence for multi‐stage diagenesis: An in‐depth component‐specific petrographic and geochemical study from Oman (mid‐Cretaceous)
Authors: Huck Stefan , Wohlwend Stephan , Coimbra Rute , Christ Nicolas , Weissert Helmut
Published: September 2017

Disentangling shallow‐water bulk carbonate carbon isotope archives into primary and diagenetic components is a notoriously difficult task and even diagenetically screened records often provide chemostratigraphic patterns that significantly differ from global signals. This is mainly caused by the polygenetic nature of shallow‐water carbonate substrates, local carbon cycle processes causing considerable neritic–pelagic isotope gradients and the presence of hiatal surfaces resulting in extremely low carbonate preservation rates. Provided here is an in‐depth petrographic and geochemical evaluation of different carbonate phases of a mid‐Cretaceous (Barremian–Aptian) shallow‐water limestone succession (Jabal Madar section) deposited on the tropical Arabian carbonate platform in Oman. The superposition of stable isotope signatures of identified carbonate phases causes a complex and often noisy bulk carbon isotope pattern. Blocky sparite cements filling intergranular pores and bioclastic voids evidence intermediate to (arguably) deep burial diagenetic conditions during their formation, owing to different timing or differential faulting promoting the circulation of fluids from variable sources. In contrast, sparite cements filling sub‐vertical veins reveal a rock‐buffered diagenetic fluid composition with an intriguing moderate enrichment in 13C, probably due to fractionation during pressure release in the context of the Miocene exhumation of the carbonate platform under study. The presence of abundant, replacive dedolomite in mud‐supported limestone samples forced negative carbon and oxygen isotope changes that are either associated with the thermal breakdown of organic matter in the deep burial realm or the expulsion of buried meteoric water in the intermediate burial realm. Notwithstanding the documented stratigraphically variable and often facies‐related impact of different diagenetic fluids on the bulk‐rock stable isotope signature, the identification of diagenetic end‐members defined δ13C and δ18O threshold values that allowed the most reliable ‘primary’ bulk carbon isotope signatures to be extracted. Most importantly, this approach exemplifies how to place regional shallow‐water stable isotope patterns with evidence for a complex multi‐stage diagenetic history into a supraregional or even global context.
Rangifer management controls a climate‐sensitive tundra state transition
Authors: Bråthen Kari Anne , Ravolainen Virve Tuulia , Stien Audun , Tveraa Torkild , Ims Rolf A.
Published: September 2017

Rangifer (caribou/reindeer) management has been suggested to mitigate the temperature‐driven transition of Arctic tundra into a shrubland state, yet how this happens is uncertain. Here we study this much focused ecosystem state transition in riparian areas, where palatable willows (Salix) are dominant tall shrubs and highly responsive to climate change. For the state transition to take place, small life stages must become tall and abundant. Therefore we predicted that the performance of small life stages (potential recruits) of the tall shrubs were instrumental to the focal transition, where Rangifer managed at high population density would keep the small‐stage shrubs in a “browse trap” independent of summer temperature. We used a large‐scale quasi‐experimental study design that included real management units that spanned a wide range of Rangifer population densities and summer temperatures in order to assess the relative importance of these two driving variables. Ground surveys provided data on density and height of the small shrub life stages, while the distributional limit (shrubline) of established shrublands (the tall shrub life stage) was derived from aerial photographs. Where Rangifer densities were above a threshold of approximately 5 animals/km2, we found, in accordance with the expectation of a “browse trap,” that the small life stages of shrubs in grasslands were at low height and low abundance. At Rangifer densities below this threshold, the small life stages of shrubs were taller and more abundant indicating Rangifer were no longer in control of the grassland state. For the established shrubland state, we found that the shrubline was at a 100‐m lower elevation in the management units where Rangifer had been browsing in summer as opposed to the migratory ranges with no browsing in summer. In both seasonal ranges, the shrubline increased 100 m per 1°C increment in temperature. Our study supports the proposal that Rangifer management within a sustainable range of animal densities can mitigate the much‐focused transition from grassland to shrubland in a warming Arctic.
Ecological niche comparison and molecular phylogeny segregate the invasive moss species Campylopus introflexus (Leucobryaceae, Bryophyta) from its closest relatives
Authors: Gama Renato , Aguirre‐Gutiérrez Jesús , Stech Michael
Published: September 2017

The delimitation of the invasive moss species Campylopus introflexus from its closest relative, Campylopus pilifer, has been long debated based on morphology. Previous molecular phylogenetic reconstructions based on the nuclear ribosomal internal transcribed spacers (ITS) 1 and 2 showed that C. pilifer is split into an Old World and a New World lineage, but remained partly inconclusive concerning the relationships between these two clades and C. introflexus. Analyses of an extended ITS dataset displayed statistically supported incongruence between ITS1 and ITS2. ITS1 separates the New World clade of C. pilifer from a clade comprising C. introflexus and the Old World C. pilifer. Ancestral state reconstruction showed that this topology is morphologically supported by differences in the height of the dorsal costal lamellae in leaf cross‐section (despite some overlap). ITS2, in contrast, supports the current morphological species concept, i.e., separating C. introflexus from C. pilifer, which is morphologically supported by the orientation of the hyaline hair point at leaf apex as well as costal lamellae height. Re‐analysis of published and newly generated plastid atpB‐rbcL spacer sequences supported the three ITS lineages. Ecological niche modeling proved a useful approach and showed that all three molecular lineages occupy distinct environmental spaces that are similar, but undoubtedly not equivalent. In line with the ITS1 topology, the C. pilifer lineage from the New World occupies the most distinct environmental niche, whereas the niches of Old World C. pilifer and C. introflexus are very similar. Taking the inferences from ecological niche comparisons, phylogenetics, and morphology together, we conclude that all three molecular lineages represent different taxa that should be recognized as independent species, viz. C. introflexus, C. pilifer (Old World clade), and the reinstated C. lamellatus Mont. (New World clade).
Woody structure facilitates invasion of woody plants by providing perches for birds
Authors: Prather Chelse M. , Huynh Andrew , Pennings Steven C.
Published: September 2017

Woody encroachment threatens prairie ecosystems globally, and thus understanding the mechanisms that facilitate woody encroachment is of critical importance. Coastal tallgrass prairies along the Gulf Coast of the US are currently threatened by the spread of several species of woody plants. We studied a coastal tallgrass prairie in Texas, USA, to determine if existing woody structure increased the supply of seeds from woody plants via dispersal by birds. Specifically, we determined if (i) more seedlings of an invasive tree (Tridacia sebifera) are present surrounding a native woody plant (Myrica cerifera); (ii) wooden perches increase the quantity of seeds dispersed to a grassland; and (iii) perches alter the composition of the seed rain seasonally in prairie habitats with differing amounts of native and invasive woody vegetation, both underneath and away from artificial wooden perches. More T. sebifera seedlings were found within M. cerifera patches than in graminoid‐dominated areas. Although perches did not affect the total number of seeds, perches changed the composition of seed rain to be less dominated by grasses and forbs. Specifically, 20–30 times as many seeds of two invasive species of woody plants were found underneath perches independent of background vegetation, especially during months when seed rain was highest. These results suggest that existing woody structure in a grassland can promote further woody encroachment by enhancing seed dispersal by birds. This finding argues for management to reduce woody plant abundance before exotic plants set seeds and argues against the use of artificial perches as a restoration technique in grasslands threatened by woody species.