bluuebunny/crossref_metadata_2025 huggingface dataset:
The effectiveness of cooling conditions on temperature of canine EDTA whole blood samples
Authors: Tobias Karen M. , Serrano Leslie , Sun Xiaocun , Flatland Bente
Published: November 2016

Background

Preanalytic factors such as time and temperature can have significant effects on laboratory test results. For example, ammonium concentration will increase 31% in blood samples stored at room temperature for 30 min before centrifugation. To reduce preanalytic error, blood samples may be placed in precooled tubes and chilled on ice or in ice water baths; however, the effectiveness of these modalities in cooling blood samples has not been formally evaluated. The purpose of this study was to evaluate the effectiveness of various cooling modalities on reducing temperature of EDTA whole blood samples.

Methods

Pooled samples of canine EDTA whole blood were divided into two aliquots. Saline was added to one aliquot to produce a packed cell volume (PCV) of 40% and to the second aliquot to produce a PCV of 20% (simulated anemia). Thirty samples from each aliquot were warmed to 37.7 °C and cooled in 2 ml allotments under one of three conditions: in ice, in ice after transfer to a precooled tube, or in an ice water bath. Temperature of each sample was recorded at one minute intervals for 15 min.

Results

Within treatment conditions, sample PCV had no significant effect on cooling. Cooling in ice water was significantly faster than cooling in ice only or transferring the sample to a precooled tube and cooling it on ice. Mean temperature of samples cooled in ice water was significantly lower at 15 min than mean temperatures of those cooled in ice, whether or not the tube was precooled. By 4 min, samples cooled in an ice water bath had reached mean temperatures less than 4 °C (refrigeration temperature), while samples cooled in other conditions remained above 4.0 °C for at least 11 min. For samples with a PCV of 40%, precooling the tube had no significant effect on rate of cooling on ice. For samples with a PCV of 20%, transfer to a precooled tube resulted in a significantly faster rate of cooling than direct placement of the warmed tube onto ice.

Discussion

Canine EDTA whole blood samples cool most rapidly and to a greater degree when placed in an ice-water bath rather than in ice. Samples stored on ice water can rapidly drop below normal refrigeration temperatures; this should be taken into consideration when using this cooling modality.
DNA structural features of eukaryotic TATA‐containing and TATA‐less promoters
Authors: Yella Venkata Rajesh , Bansal Manju
Published: November 2016

Eukaryotic genes can be broadly classified as TATA‐containing and TATA‐less based on the presence of TATA box in their promoters. Experiments on both classes of genes have revealed a disparity in the regulation of gene expression and cellular functions between the two classes. In this study, we report characteristic differences in promoter sequences and associated structural properties of the two categories of genes in six different eukaryotes. We have analyzed three structural features, DNA duplex stability, bendability, and curvature along with the distribution of A‐tracts, G‐quadruplex motifs, and CpG islands. The structural feature analyses reveal that while the two classes of gene promoters are distinctly different from each other, the properties are also distinguishable across the six organisms.
Sandcastle Worm‐Inspired Blood‐Resistant Bone Graft Binder Using a Sticky Mussel Protein for Augmented In Vivo Bone Regeneration
Authors: Kim Hyo Jeong , Choi Bong‐Hyuk , Jun Sang Ho , Cha Hyung Joon
Published: November 2016

Xenogenic bone substitutes are commonly used during orthopedic reconstructive procedures to assist bone regeneration. However, huge amounts of blood accompanied with massive bone loss usually increase the difficulty of placing the xenograft into the bony defect. Additionally, the lack of an organic matrix leads to a decrease in the mechanical strength of the bone‐grafted site. For effective bone grafting, this study aims at developing a mussel adhesion‐employed bone graft binder with great blood‐resistance and enhanced mechanical properties. The distinguishing water (or blood) resistance of the binder originates from sandcastle worm‐inspired complex coacervation using negatively charged hyaluronic acid (HA) and a positively charged recombinant mussel adhesive protein (rMAP) containing tyrosine residues. The rMAP/HA coacervate stabilizes the agglomerated bone graft in the presence of blood. Moreover, the rMAP/HA composite binder enhances the mechanical and hemostatic properties of the bone graft agglomerate. These outstanding features improve the osteoconductivity of the agglomerate and subsequently promote in vivo bone regeneration. Thus, the blood‐resistant coacervated mussel protein glue is a promising binding material for effective bone grafting and can be successfully expanded to general bone tissue engineering.
Graphene‐Based Biosensors: Going Simple
Authors: Morales‐Narváez Eden , Baptista‐Pires Luis , Zamora‐Gálvez Alejandro , Merkoçi Arben
Published: November 2016

The main properties of graphene derivatives facilitating optical and electrical biosensing platforms are discussed, along with how the integration of graphene derivatives, plastic, and paper can lead to innovative devices in order to simplify biosensing technology and manufacture easy‐to‐use, yet powerful electrical or optical biosensors. Some crucial issues to be overcome in order to bring graphene‐based biosensors to the market are also underscored.
Diskrete Silber(I)‐Palladium(II)‐Oxo‐Nanocluster, {Ag4Pd13} und {Ag5Pd15}, sowie die Rolle der Metall‐Metall‐Bindung induziert durch Kationen‐Einschluss
Authors: Yang Peng , Xiang Yixian , Lin Zhengguo , Lang Zhongling , Jiménez‐Lozano Pablo , Carbó Jorge J. , Poblet Josep M. , Fan Linyuan , Hu Changwen , Kortz Ulrich
Published: November 2016

Die beiden diskreten Silber(I)‐Palladium(II)‐Oxo‐Nanocluster {Ag4Pd13} und {Ag5Pd15} sind die ersten Beispiele von edelmetallverkappten Polyoxoedelmetallaten mit einem neuartigen Wirt‐Gast‐Bindungsmodus, der hetero‐ und homometallische Ag‐Pd‐ und Ag‐Ag‐Wechselwirkungen beinhaltet. Umfassende theoretische Studien deuten darauf hin, dass die Ag‐Pd‐Metallbindungen teilweise von einem Polyanion‐Oberflächeneffekt auf die AgI‐Gastionen herrühren, der durch starke elektrostatische Kräfte induziert wird. Diese Arbeit eröffnet ein Gebiet komplett anorganischer Silber‐Palladium‐Oxo‐Nanocluster, die als Vorstufen für die Bildung monodisperser Kern‐Schale‐Nanopartikel angesehen werden können, welche eine hohe Relevanz im Bereich der Katalyse haben.
Modification of Bi2WO6 composites with rGO for enhanced visible light driven NO removal
Authors: Wang L. , Sun B. , Wang W. , Feng L. , Li Q. , Li C.
Published: November 2016

Bi2WO6‐rGO composites were synthesized through hydrothermal method. Its visible‐light‐driven photocatalytic properties were evaluated by the oxidation of nitrogen monoxide, which exhibited significantly enhancement on the photocatalytic performance comparing with Bi2WO6. Bi2WO6–2% rGO showed the highest photocatalytic activity for NO removal. The enhanced photocatalytic activity can be attributed to the increased light absorption and more effective charge transportation and separation arisen from the strong chemical bonding between Bi2WO6 and rGO. The results on the effects of H2O and SO2 concentration to NO removal efficiency indicate that the activity of Bi2WO6–2% rGO composite was suppressed by the coexisting of SO2 while promoted by H2O. In addition, the reaction mechanism of the photocatalytic oxidation of NO to NO2 was also discussed. © 2016 Curtin University of Technology and John Wiley & Sons, Ltd. © 2016 Curtin University of Technology and John Wiley & Sons, Ltd.
One simple and stable coating of mixed‐charge copolymers on poly(vinyl chloride) films to improve antifouling efficiency
Authors: Zhang Ling , Tang Minjie , Zhang Jinwei , Zhang Pengsheng , Zhang Jianhua , Deng Liandong , Lin Cunguo , Dong Anjie
Published: November 2016

An antifouling surface is highly desirable for many biomedical applications. In this study, poly(vinyl chloride) (PVC) films were endowed with the improved properties of resisting nonspecific protein adsorption and platelet adhesion simply through being coated with a kind of mixed‐charge zwitterionic polymer, poly(3‐sulfopropyl methacrylate–methacrylatoethyl trimethyl ammonium chloride–glycidyl methacrylate) (PSTG), with random moieties of negatively charged 3‐sulfopropyl methacrylate potassium, positively charged [2‐(methacryloyloxy)‐ethyl] trimethylammonium chloride, and glycidyl methacrylate. The PSTG‐grafted PVC films were formed by the simple immersion of an amino‐functionalized PVC film into a PSTG solution. A grafting density of 220.84 µg/cm2 of PSTG4‐grafted PVC film was successfully obtained. The PSTG4‐grafted PVC film showed a lower contact angle (37.5 °) than the ungrafted PVC film (98.3 °). The in vitro protein adsorption results show that the bovine serum albumin adsorption amount decreased 6.72 µg/cm2 in the case of the PSTG4‐grafted PVC film, whereas that on the ungrafted PVC film was 28.54 µg/cm2. So, PSTG‐grafted PVC films could be promising materials for medical devices. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44632.
Comparison of thermoset soy protein resin toughening by natural rubber and epoxidized natural rubber
Authors: Kim Joo Ran , Netravali Anil N.
Published: November 2016

Fully bio‐based soy protein isolate (SPI) resins were toughened using natural rubber (NR) and epoxidized natural rubber (ENR). Resin compositions containing up to 30 wt % NR or ENR were prepared and characterized for their physical, chemical and mechanical properties. Crosslinking between SPI and ENR was confirmed using 1H‐NMR and ATR‐FTIR. All SPI/NR resins exhibited two distinctive drops in their modulus at glass transition temperature (Tg) and degradation temperature (Td) at around −50 and 215 °C, corresponding to major segmental motions of NR and SPI, respectively. SPI/ENR resins showed similar Tg and Td transitions at slightly higher temperatures. For SPI/ENR specimens the increase in ENR content from 0 to 30 wt % showed major increase in Tg from −23 to 13 °C as a result of crosslinking between SPI and ENR. The increase in ENR content from 0 to 30 wt % increased the fracture toughness from 0.13 to 1.02 MPa with minimum loss of tensile properties. The results indicated that ENR was not only more effective in toughening SPI than NR but the tensile properties of SPI/ENR were also significantly higher than the corresponding compositions of SPI/NR. SPI/ENR green resin with higher toughness could be used as fully biodegradable thermoset resin in many applications including green composites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44665.
Unprecedented Reaction Pathway of Sterically Crowded Calcium Complexes: Sequential C−N Bond Cleavage Reactions Induced by C−H Bond Activations
Authors: Yang Yang , Wang Haobing , Ma Haiyan
Published: November 2016

Five bis(quinolylmethyl)‐(1H‐indolylmethyl)amine (BQIA) compounds, that is, {(quinol‐8‐yl‐CH2)2NCH2(3‐Br‐1H‐indol‐2‐yl)} (L1H) and {[(8‐R3‐quinol‐2‐yl)CH2]2NCH(R2)[3‐R1‐1H‐indol‐2‐yl]} (L2–5H) (L2H: R1=Br, R2=H, R3=H; L3H: R1=Br, R2=H, R3=iPr; L4H: R1=H, R2=CH3, R3=iPr; L5H: R1=H, R2=nBu, R3=iPr) were synthesized and used to prepare calcium complexes. The reactions of L1–5H with silylamido calcium precursors (Ca[N(SiMe2R)2]2(THF)2, R=Me or H) at room temperature gave heteroleptic products (L1, 2)CaN(SiMe3)2 (1, 2), (L3, 4)CaN(SiHMe2)2 (3 a, 4 a) and homoleptic complexes (L3, 5)2Ca (D3, D5). NMR and X‐ray analyses proved that these calcium complexes were stabilized through Ca⋅⋅⋅C−Si, Ca⋅⋅⋅H−Si or Ca⋅⋅⋅H−C agostic interactions. Unexpectedly, calcium complexes ((L3–5)CaN(SiMe3)2) bearing more sterically encumbered ligands of the same type were extremely unstable and underwent C−N bond cleavage processes as a consequence of intramolecular C−H bond activation, leading to the exclusive formation of (E)‐1,2‐bis(8‐isopropylquinol‐2‐yl)ethane.
An Obtuse‐angled Corner Unit for Fluctuating Carbon Nanohoops
Authors: Sun Zhe , Miyamoto Naoya , Sato Sota , Tokuyama Hidetoshi , Isobe Hiroyuki
Published: November 2016

The invention of corner units was the key factor that allowed the synthesis of cyclo‐para‐phenylenes with strained curved π‐systems. Despite only a few scarce instances of the development of corner units to date, a variety of structural congeners have been synthesized. These preceding corner units commonly possessed directing angles of ≤90°, which enabled the macrocyclization of multiple units, up to six. In this study, we introduce an obtuse‐angled corner unit for the synthesis of cyclo‐para‐phenylene congeners. The corner unit with oxanorbornadiene possessed a directing angle of 126° and thus allowed for the macrocyclization of larger structures with up to seven units. Reductive aromatization was applicable to complete the cyclo‐para‐phenylene structures and afforded the congeners with multiple anthracenylene panels. Structural studies with experimental and theoretical methods revealed a fluctuating structure with an intrinsic non‐belt shape.
Fitting peculiar spectral profiles in He I 10830 Å absorption features
Authors: González Manrique S. J. , Kuckein C. , Pastor Yabar A. , Collados M. , Denker C. , Fischer C. E. , Gömöry P. , Diercke A. , Bello González N. , Schlichenmaier R. , Balthasar H. , Berkefeld T. , Feller A. , Hoch S. , Hofmann A. , Kneer F. , Lagg A. , Nicklas H. , Orozco Suárez D. , Schmidt D. , Schmidt W. , Sigwarth M. , Sobotka M. , Solanki S. K. , Soltau D. , Staude J. , Strassmeier K. G. , Verma M. , Volkmer R. , von der Lühe O. , Waldmann T.
Published: November 2016

The new generation of solar instruments provides better spectral, spatial, and temporal resolution for a better understanding of the physical processes that take place on the Sun. Multiple‐component profiles are more commonly observed with these instruments. Particularly, the Hei 10830 Å triplet presents such peculiar spectral profiles, which give information on the velocity and magnetic fine structure of the upper chromosphere. The purpose of this investigation is to describe a technique to efficiently fit the two blended components of the Hei 10830 Å triplet, which are commonly observed when two atmospheric components are located within the same resolution element. The observations used in this study were taken on 2015 April 17 with the very fast spectroscopic mode of the GREGOR Infrared Spectrograph (GRIS) attached to the 1.5‐m GREGOR solar telescope, located at the Observatorio del Teide, Tenerife, Spain. We apply a double‐Lorentzian fitting technique using Levenberg‐Marquardt least‐squares minimization. This technique is very simple and much faster than inversion codes. Line‐of‐sight Doppler velocities can be inferred for a whole map of pixels within just a few minutes. Our results show sub‐ and supersonic downflow velocities of up to 32km s–1 for the fast component in the vicinity of footpoints of filamentary structures. The slow component presents velocities close to rest. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Solar eruptions: The CME‐flare relationship
Authors: Vršnak B.
Published: November 2016

Coronal mass ejections (CMEs), caused by large‐scale eruptions of the coronal magnetic field, often are accompanied by a more localized energy release in the form of flares, as a result of dissipative magnetic‐field reconfiguration. Morphology and evolution of such flares, also denoted as dynamical flares are often explained as a consequence of reconnection of the arcade magnetic field, taking place below the erupting magnetic flux rope. A close relationship of the CME acceleration and the flare energy release is evidenced by various statistical correlations between parameters describing CMEs and flares, as well as by the synchronization of the CME acceleration phase with the impulsive phase of the associated flare. Such behavior implies that there must be a feedback relation between the dynamics of the CME and the flare‐associated reconnection process. From the theoretical standpoint, magnetic reconnection affects the CME dynamics in several ways. First, it reduces the tension of the overlying arcade magnetic field and increases the magnetic pressure below the flux rope, and in this way enhances the CME acceleration. Furthermore, it supplies the poloidal magnetic flux to the flux rope, which helps sustaining the electric current in the rope and prolonging the action of the driving Lorentz force to large distances. The role of these processes, directly relating solar flares and CMEs, is illustrated by employing a simple model, where the erupting structure is represented by a curved flux rope anchored at both sides in the dense/inert photosphere, being subject to the kink and torus instability. It is shown that in most strongly accelerated ejections, where values on the order of 10km s–2 are attained, the poloidal flux supplied to the erupting rope has to be several times larger than was the initial flux. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Kinematical properties of coronal mass ejections
Authors: Temmer M.
Published: November 2016

Coronal mass ejections (CMEs) are the most dynamic phenomena in our solar system. They abruptly disrupt the continuous outflow of solar wind by expelling huge clouds of magnetized plasma into interplanetary space with velocities enabling to cross the Sun‐Earth distance within a few days. Earth‐directed CMEs may cause severe geomagnetic storms when their embedded magnetic fields and the shocks ahead compress and reconnect with the Earth's magnetic field. The transit times and impacts in detail depend on the initial CME velocity, size, and mass, as well as on the conditions and coupling processes with the ambient solar wind flow in interplanetary space. The observed CME parameters may be severely affected by projection effects and the constant changing environmental conditions are hard to derive. This makes it difficult to fully understand the physics behind CME evolution, preventing to do a reliable forecast of Earth‐directed events. This short review focusing on observational data, shows recent methods which were developed to derive the CME kinematical profile for the entire Sun‐Earth distance range as well as studies which were performed to shed light on the physical processes that CMEs encounter when propagating from Sun to Earth. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Observations of solar X‐ray and EUV jets and their related phenomena
Authors: Innes D. E. , Bučík R. , Guo L.‐J. , Nitta N.
Published: November 2016

Solar jets are fast‐moving, elongated brightenings related to ejections seen in both images and spectra on all scales from barely visible chromospheric jets to coronal jets extending up to a few solar radii. The largest, most powerful jets are the source of type III radio bursts, energetic electrons and ions with greatly enhanced 3He and heavy element abundances. The frequent coronal jets from polar and equatorial coronal holes may contribute to the solar wind. The primary acceleration mechanism for all jets is believed to be release of magnetic stress via reconnection; however the energy buildup depends on the jets' source environment. In this review, we discuss how certain features of X‐ray and EUV jets, such as their repetition rate and association with radio emission, depends on their underlying photospheric field configurations (active regions, polar and equatorial coronal holes, and quiet Sun). (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chromospheric activity in sunspot light bridges
Authors: Louis R. E.
Published: November 2016

High‐resolution filtergrams from Hinode were used to analyse the nature of chromospheric activity over a set of five sunspot light bridges. The broad‐band Ca II H filtergrams depict a variety of phenomena which include large arc‐shaped brightenings, bright patches, and small‐scale jets. These strong brightenings are recurrent over a duration of several hours and appear to be a common attribute of a sunspot light bridge, independent of its photospheric morphology and horizontal flow pattern. Hinode spectro‐polarimetric observations were used to construct far wing magnetograms from the Fe I line at 630.25 nm, which reveal the presence of small‐scale magnetic and velocity inhomogeneities in the photosphere of the light bridges. Although there is strong evidence for a causal relation between the photospheric anomalies and the observed chromospheric activity, the physical mechanism responsible for the latter remains speculative. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectropolarimetric observations of an arch filament system with the GREGOR solar telescope
Authors: Balthasar H. , Gömöry P. , González Manrique Sj. , Kuckein C. , Kavka J. , Kučera A. , Schwartz P. , Vašková R. , Berkefeld T. , Collados Vera M. , Denker C. , Feller A. , Hofmann A. , Lagg A. , Nicklas H. , Orozco Suárez D. , Pastor Yabar A. , Rezaei R. , Schlichenmaier R. , Schmidt D. , Schmidt W. , Sigwarth M. , Sobotka M. , Solanki S.K. , Soltau D. , Staude J. , Strassmeier K. G. , Volkmer R. , von der Lühe O. , Waldmann T.
Published: November 2016

Arch filament systems occur in active sunspot groups, where a fibril structure connects areas of opposite magnetic polarity, in contrast to active region filaments that follow the polarity inversion line. We used the GREGOR Infrared Spectrograph (GRIS) to obtain the full Stokes vector in the spectral lines Si I λ 1082.7 nm, He I λ 1083.0 nm, and Ca I λ 1083.9 nm. We focus on the near‐infrared calcium line to investigate the photospheric magnetic field and velocities, and use the line core intensities and velocities of the helium line to study the chromospheric plasma. The individual fibrils of the arch filament system connect the sunspot with patches of magnetic polarity opposite to that of the spot. These patches do not necessarily coincide with pores, where the magnetic field is strongest. Instead, areas are preferred not far from the polarity inversion line. These areas exhibit photospheric downflows of moderate velocity, but significantly higher downflows of up to 30 km s–1 in the chromospheric helium line. Our findings can be explained with new emerging flux where the matter flows downward along the field lines of rising flux tubes, in agreement with earlier results. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Daniel K. Inouye Solar Telescope: High‐resolution observing of the dynamic Sun
Authors: Tritschler A. , Rimmele T. R. , Berukoff S. , Casini R. , Kuhn J. R. , Lin H. , Rast M. P. , McMullin J. P. , Schmidt W. , Wöger F. , DKIST Team
Published: November 2016

The 4‐m aperture Daniel K. Inouye Solar Telescope (DKIST) formerly known as the Advanced Technology Solar Telescope (ATST) is currently under construction on Haleakalā (Maui, Hawai'i) projected to start operations in 2019. At the time of completion, DKIST will be the largest ground‐based solar telescope providing unprecedented resolution and photon collecting power. The DKIST will be equipped with a set of first‐light facility‐class instruments offering unique imaging, spectroscopic and spectropolarimetric observing opportunities covering the visible to infrared wavelength range. This first‐light instrumentation suite will include: a Visible Broadband Imager (VBI) for high‐spatial and ‐temporal resolution imaging of the solar atmosphere; a Visible Spectro‐Polarimeter (ViSP) for sensitive and accurate multi‐line spectropolarimetry; a Fabry‐Pérot based Visible Tunable Filter (VTF) for high‐spatial resolution spectropolarimetry; a fiber‐fed Diffraction‐Limited Near Infra‐Red Spectro‐Polarimeter (DL‐NIRSP) for two‐dimensional high‐spatial resolution spectropolarimetry (simultaneous spatial and spectral information); and a Cryogenic Near Infra‐Red Spectro‐Polarimeter (Cryo‐NIRSP) for coronal magnetic field measurements and on‐disk observations of, e.g., the CO lines at 4.7 μm. We will provide an overview of the DKISTs unique capabilities with strong focus on the first‐light instrumentation suite, highlight some of the additional properties supporting observations of transient and dynamic solar phenomena, and touch on some operational strategies and the DKIST critical science plan. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On measurements of the Balmer continuum flux in a solar flare: Analysis of pre‐flare and flare pulsations
Authors: Zapiór M. , Kotrč P. , Oliver R. , Procházka O. , Heinzel P.
Published: November 2016

A new ground based device for the measurement of the Balmer continuum flux in solar flares was recently developed and installed at the Ondřejov Observatory. We observed an X1 solar flare on 2014 June 11 during its pre‐flare and impulsive phases using a wide band spectrometer with a cadence of 1 s. The Ensemble Empirical Mode Decomposition (EEMD) of the registered signal was performed. We found damped oscillations with a period of 609 s and damping time of 1478 s. Shorter periods of about 30–120 s were found during the pre‐flare and impulsive phases, but they might be of non‐flare origin
STAT3 targeting by polyphenols: Novel therapeutic strategy for melanoma
Authors: Momtaz Saeideh , Niaz Kamal , Maqbool Faheem , Abdollahi Mohammad , Rastrelli Luca , Nabavi Seyed Mohammad
Published: November 2016

Melanoma or malignant melanocytes appear with the low incidence rate, but very high mortality rate worldwide. Epidemiological studies suggest that polyphenolic compounds contribute for prevention or treatment of several cancers particularly melanoma. Such findings motivate to dig out novel therapeutic strategies against melanoma, including research toward the development of new chemotherapeutic and biologic agents that can target the tumor cells by different mechanisms. Recently, it has been found that signal transducer and activator of transcription 3 (STAT3) is activated in many cancer cases surprisingly. Different evidences supply the aspect that STAT3 activation plays a vital role in the metastasis, including proliferation of cells, survival, invasion, migration, and angiogenesis. This significant feature plays a vital role in various cellular processes, such as cell proliferation and survival. Here, we reviewed the mechanisms of the STAT3 pathway regulation and their role in promoting melanoma. Also, we have evaluated the emerging data on polyphenols (PPs) specifically their contribution in melanoma therapies with an emphasis on their regulatory/inhibitory actions in relation to STAT3 pathway and current progress in the development of phytochemical therapeutic techniques. An understanding of targeting STAT3 by PPs brings an opportunity to melanoma therapy. © 2016 BioFactors, 43(3):347–370, 2017
Small‐Molecule‐Induced and Cooperative Enzyme Assembly on a 14‐3‐3 Scaffold
Authors: den Hamer Anniek , Lemmens Lenne J. M. , Nijenhuis Minke A. D. , Ottmann Christian , Merkx Maarten , de Greef Tom F. A. , Brunsveld Luc
Published: November 2016

Scaffold proteins regulate cell signalling by promoting the proximity of putative interaction partners. Although they are frequently applied in cellular settings, fundamental understanding of them in terms of, amongst other factors, quantitative parameters has been lagging behind. Here we present a scaffold protein platform that is based on the native 14‐3‐3 dimeric protein and is controllable through the action of a small‐molecule compound, thus permitting study in an in vitro setting and mathematical description. Robust small‐molecule regulation of caspase‐9 activity through induced dimerisation on the 14‐3‐3 scaffold was demonstrated. The individual parameters of this system were precisely determined and used to develop a mathematical model of the scaffolding concept. This model was used to elucidate the strong cooperativity of the enzyme activation mediated by the 14‐3‐3 scaffold. This work provides an entry point for the long‐needed quantitative insights into scaffold protein functioning and paves the way for the optimal use of reengineered 14‐3‐3 proteins as chemically inducible scaffolds in synthetic systems.
Plant‐Mediated Synthesis of Zinc Oxide Supported Nickel‐Palladium Alloy Catalyst for the Selective Hydrogenation of 1,3‐Butadiene
Authors: Huang Jiale , Odoom‐Wubah Tareque , Jing Xiaolian , Sun Daohua , Gu Zhengqiang , Li Qingbiao
Published: November 2016

We report the green synthesis of ZnO‐supported Ni‐Pd alloy nanoparticles for the gas‐phase selective hydrogenation of 1,3‐butadiene. The supported catalysts were synthesized through a simple bioreduction route using Cinnamomum Camphora leaf extract. We used XRD, SEM, TEM, and energy‐dispersive X‐ray spectroscopy to characterize and verify the nature of the catalysts. The results showed that the size of the Ni‐Pd alloy particles was (3.2±0.7), (3.4±0.3), and (3.8±0.6) nm for Ni1Pd1, Ni1Pd3, and Ni3Pd1 respectively. FTIR spectroscopy revealed that the presence of stretching vibrations from C−H, −C=C−, O−H, and −C−O−O groups that remained on the surface and act as stabilizers. The influence of some reaction variables, such as the type of S‐Pd (S=Au, Ag, Ni) bimetallic catalyst, the type of metal oxide support, and the reaction temperature, on the hydrogenation activity and selectivity towards total butene (trans‐2‐butene, 1‐butene, and cis‐2‐butene) is investigated. The bioreduced, supported catalysts showed excellent catalytic activity and selectivity to butene in the selective hydrogenation of 1,3‐butadiene. The calculated total butene selectivity was above 80 % for all supported S1‐Pd1 catalysts compared to 46.92 % for a monometallic Pd/ZnO catalyst. In addition, the Ni1‐Pd1/ZnO catalyst presented the best butene yield of 88.90 %, which was 1.9 times that of the Pd/ZnO catalyst. Moreover, it remained stable over a 10 h durability experiment.
Freestanding Catalyst Layers: A Novel Electrode Fabrication Technique for PEM Fuel Cells via Electrospinning
Authors: Kayarkatte Manoj Krishna , Delikaya Öznur , Roth Christina
Published: November 2016

To propel the commercial success of fuel cells, increased Pt catalyst utilization is preeminent. To achieve this, advanced 3D scaffold electrode architecture with controllable porosity, thickness, etc. should be developed. Here, we present a novel technique for the fabrication of electrode structures through electrospinning, which is not only tailorable, but inexpensive and scalable. The structure is freestanding and contains carbon nanotube‐enforced carbon nanofibers, which give the electrode its structure. Pt is decorated on the surface of the fiber structures through impregnation of a Pt precursor and successive reduction. The electrode structure is hot‐pressed by inserting it between a gas diffusion layer (GDL) and a membrane to form the cathode. The novel fabrication technique is versatile and can be used to prepare electrodes of different morphologies. In this work, we demonstrate the technique by preparing a highly porous network, which shows a very high Pt utilization of approximately 90% for a loading of 0.3 mgPt cm−2. In comparison, a standard electrode prepared via a hot‐spray technique has a catalyst utilization of 60% for the same loading.
Selective B(4)−H Activation of an o‐Carboranylthioamide Based on a Palladium Precursor
Authors: Wang Yin‐Ping , Zhang Long , Lin Yue‐Jian , Li Zhen‐Hua , Jin Guo‐Xin
Published: November 2016

Palladium(II)‐induced selective B(4)−H activation of an o‐carboranylthioamide has been developed. A tetranuclear palladium(II) complex has been obtained in high yield with excellent regioselectivity. DFT calculations have confirmed that the B(4)‐borometalate is lower in energy than the corresponding B(3)‐borometalate. The product proved to be a good precursor for target mononuclear or trinuclear B(4)−H activated complexes.
One‐Step Synthesis of Boron Nitride Quantum Dots: Simple Chemistry Meets Delicate Nanotechnology
Authors: Liu Bingping , Yan Shihai , Song Zhongqian , Liu Mengli , Ji Xuqiang , Yang Wenrong , Liu Jingquan
Published: November 2016

Herein, a conceptually new and straightforward aqueous route is described for the synthesis of hydroxyl‐ and amino‐functionalized boron nitride quantum dots (BNQDs) with quantum yields (QY) as high as 18.3 % by using a facile bottom‐up approach, in which a mixture of boric acid and ammonia solution was hydrothermally treated in one pot at 200 °C for 12 h. The functionalized BNQDs, with excellent photoluminescence properties, could be easily dispersed in an aqueous medium and applied as fluorescent probes for the detection of ferrous (Fe2+) and ferric (Fe3+) ions with excellent selectivity and low detection limits. The mechanisms for the hydrothermal reaction and fluorescence quenching were also simulated by using density functional theory (DFT), which confirmed the feasibility and advantages of this strategy. It provides a scalable and eco‐friendly method for preparation of BNQDs with good dispersability and could also be generalized to the synthesis of other 2D quantum dots and nanoplates.
Bulky Ytterbium Formamidinates Stabilise Complexes with Radical Ligands, and Related Samarium “Tetracyclone” Chemistry
Authors: Werner Daniel , Zhao Xuefei , Best Stephen P. , Maron Laurent , Junk Peter C. , Deacon Glen B.
Published: November 2016

Divalent [Yb(DippForm)2(thf)n] (n=2 (1 a), or 1 (1 b), DippForm=N,N′‐bis(2,6‐diisopropylphenyl)formamidinate) complexes were treated with the ketones: 9‐fluorenone (fn), or 2,3,4,5‐tetraphenylcyclopentadienone (tpc, tetracyclone), giving ketyl complexes: [Yb(DippForm)2(fn.‐O)(thf)] (2), and [Yb(DippForm)2(tpc.‐O)] (3), respectively (ketyl=a radical anion containing a C.−O(−) group. By contrast, when perfluorobenzophenone (pfb) was treated with either 1 a or 1 b, transitory ketyl formation was followed by rapid decomposition through a C−F activation pathway, giving [YbF(DippForm)2(thf)] (4 a) and a highly unusual fluoride/oxide‐bridged species: [Yb5F6O2(DippForm)5] (4 b). The reduction of diketones: 3,5‐di‐tert‐butyl‐1,2‐benzoquinone (tbbq), 9,10‐phenanthrenequinone (phen), or 1,2‐acenaphthenequinone (acen), was also examined giving ketyl complexes: [Yb(DippForm)2(tbbq.‐O2)] (5), [Yb(DippForm)2(phen.‐O2)] (6), and [Yb(DippForm)2(acen.‐O2)(thf)] (7). An unsolvated derivative of 7, namely [Yb(DippForm)2(acen.‐O2)] (8), was obtained from PhMe. All ketyl complexes had suitably elongated C.−O bonds, were stable in both polar and non‐polar solvents—an uncommon trait for rare‐earth ketyl complexes—and, with the exception of 3, showed radical signals in ESR spectra. To investigate the reactivity of the tpc.‐O ketyl complex, 3 was treated with oxidants (CS2, Se) and reducing agents (Mg0, KH, or [SmI2(thf)2]). Thus 3 was oxidised to tpc by Se. Treatment of 3 with KH led to a ligand exchange process giving an unusual diketyl species [Yb(DippForm)(tpc.‐O)2(thf)2] (10), which has two cisoid tpc.‐O− ligands in very close proximity. When treated with [SmI2(thf)2], the tpc.‐O ketyl was further reduced to a dianion (1‐oxido‐2,3,4,5‐tetraphenylcyclopentadianide2−), ({C5Ph4}‐O)2− by [SmI2(thf)2], giving dimeric [{SmI({C5Ph4}‐O)(thf)2}2] (Sm11) and monomeric complexes [YbI(DippForm)2(thf)] (11 b) and [YbI2(DippForm)(thf)2] (11 c). Activated Sm metal reduced neutral tetracyclone to the dianion, ({C5Ph4}‐O)2−, in THF, giving tetranuclear [{SmII2({C5Ph4}‐O)2(thf)3}2] (Sm13). Treatment of Sm13 with iodine in situ provided access to [{SmI({C5Ph4}‐O)(thf)2}2] (Sm11), in good yield.
Spectroscopic, Structural, and Kinetic Investigation of the Ultrafast Spin Crossover in an Unusual Cobalt(II) Semiquinonate Radical Complex
Authors: Rupp Fabian , Chevalier Katharina , Graf Michèle , Schmitz Markus , Kelm Harald , Grün Anneken , Zimmer Manuel , Gerhards Markus , van Wüllen Christoph , Krüger Hans‐Jörg , Diller Rolf
Published: November 2016

A comprehensive spectroscopic and structural investigation of [CoII(l‐N4 tBu2)(dbsq)][B(p‐C6H4Cl)4] (1, l‐N4 tBu2=N,N′‐di‐tert‐butyl‐2,11‐diaza[3.3](2,6)pyridinophane, dbsq1−=3,5‐di‐tert‐butylsemiquinonate), the first known octahedral complex with a low‐spin (ls) CoII semiquinonate ground state, is reported. Above 200 K, solids as well as solutions of 1 exhibit thermally induced spin‐crossover (SCO) from the ls to the high‐spin (hs) CoII semiquinonate state instead of the frequently observed valence tautomerism from ls CoIII catecholate to hs CoII semiquinonate. DFT calculations demonstrate that the (closed shell) CoIII catecholate suffers from a triplet instability leading to the ls CoII semiquinonate ground state. The thorough temperature‐dependent spectroscopic study of the SCO enables a photophysical investigation. Thus, by selective photoexcitation of the ls fraction of 1 in solution at room temperature, ultrafast conversion to the hs state is observed using femtosecond electronic and IR‐vibrational (infrared) transient absorption spectroscopy. The kinetics of the photocycle is described by a stretched exponential with τ=3.3–3.6 ps and β=0.52–0.54, representing an upper limit for the hs–ls relaxation time. This is, to our knowledge, the fastest interconversion ever determined for a SCO complex, and is attributed to the special situation that in 1 a CoII complex is coordinated to a π‐radical ligand allowing very efficient coupling between the ls and hs spin states.
Quantitative Investigation of the Structural, Thermal, and Mechanical Properties of Polymorphs of a Fluorinated Amide
Authors: Mondal Pradip Kumar , Kiran M. S. R. N. , Ramamurty U. , Chopra Deepak
Published: November 2016

The discovery of three polymorphs of N‐(3,5‐difluorophenyl)‐2,4‐difluorobenzamide, of which two exist as concomitant polymorphs, highlights the significance of short, linear C−H⋅⋅⋅F intermolecular interactions in the solid state. The formation of these polymorphs can be regulated by monitoring the scan rate in differential scanning calorimetry. The phases have been characterized structurally and the investigation of the mechanical properties depicts that Form 1 is stiffer and harder than Form 2 by 50 % and 33 %, respectively.
Magnetic Tuning of an Anionic CoII‐MOF through Deionization of the Framework: Spin‐Canting, Spin‐Flop, and Easy‐Plane Magnetic Anisotropy
Authors: Tian Chong‐Bin , Han Yun‐Hu , He Zhang‐Zhen , Du Shao‐Wu
Published: November 2016

An anionic CoII‐MOF, (Me2NH2)[Co3(Me2NH)3(OH)(SDBA)3] (1) (H2SDBA=4,4′‐sulfonyldibenzoic acid) consisting of highly symmetric CoII3(μ3‐OH) triangles exhibits spin‐canting, spin‐flop, and easy‐plane magnetic anisotropy. Measurement on a single crystal shows that the ab plane of 1 is the easy magnetization plane. After structural modification through simultaneous removal of the coordinated dimethylamine (DMA) molecule at the Co center and the ionic groups DMA+ and OH−, the resulting neutral amorphous framework 2 displays an enhanced spin frustration effect. The deionization of 1 does not result in the collapse of the framework, showing the high stability of the backbone structure.
The Role of Coordination Environment and pH in Tuning the Oxidation Rate of Europium(II)
Authors: Ekanger Levi A. , Basal Lina A. , Allen Matthew J.
Published: November 2016

The EuII/III redox couple offers metal‐based oxidation‐sensing with magnetic resonance imaging making the study of EuII oxidation chemistry important in the design of new probes. Accordingly, we explored oxidation reactions with a set of EuII‐containing complexes. Superoxide formation from the reaction between EuII and dioxygen was observed using electron paramagnetic resonance spectroscopy. Additionally, oxidation kinetics of three EuII‐containing complexes with bromate and glutathione disulfide at pH values, including 5 and 7, is reported. In the reaction with bromate, the oxidation rate of two of the complexes increased by 7.3 and 6.7 times upon decreasing pH from 7 to 5, but the rate increased by 17 times for a complex containing amide functional groups over the same pH range. The oxidation rate of a fluorobenzo‐functionalized cryptate was relatively slow, indicating that the ligand used to impart thermodynamic oxidative stability might also be useful for controlling oxidation kinetics.
Tailoring Colors by O Annulation of Polycyclic Aromatic Hydrocarbons
Authors: Miletić Tanja , Fermi Andrea , Orfanos Ioannis , Avramopoulos Aggelos , De Leo Federica , Demitri Nicola , Bergamini Giacomo , Ceroni Paola , Papadopoulos Manthos G. , Couris Stelios , Bonifazi Davide
Published: November 2016

The synthesis of O‐doped polyaromatic hydro‐ carbons in which two polycyclic aromatic hydrocarbon sub units are bridged through one or two O atoms has been achieved. This includes high‐yield ring‐closure key steps that, depending on the reaction conditions, result in the formation of furanyl or pyranopyranyl linkages through intramolecular C−O bond formation. Comprehensive photophysical measurements in solution showed that these compounds have exceptionally high emission yields and tunable absorption properties throughout the UV/Vis spectral region. Electrochemical investigations showed that in all cases O annulation increases the electron‐donor capabilities by raising the HOMO energy level, whereas the LUMO energy level is less affected. Moreover, third‐order nonlinear optical (NLO) measurements on solutions or thin films containing the dyes showed very good values of the second hyperpolarizability. Importantly, poly(methyl methacrylate) films containing the pyranopyranyl derivatives exhibited weak linear absorption and NLO absorption compared to the nonlinearity and NLO refraction, respectively, and thus revealed them to be exceptional organic materials for photonic devices.
Organic Matter Impact on Distribution of Rare Earth Elements in Soil Under Different Land Uses
Authors: Han Guilin , Li Fushan , Tang Yang
Published: November 2016

This study investigated the enrichment and fractionation of rare earth elements (REE) in soils with different soil organic carbon (SOC) concentrations under diverse land uses. The results indicated that there were significant and important differences in soil REE behavior. Their fractionation was strongly and negatively correlated to the middle REE (MREE) and SOC implying that soil organic matter (SOM) acts as the host phase for the REE. Higher total REE concentrations in sites dominated by C4 plants than those dominated by C3 plants, and the significant negative correlation between δ13C and MREE indicated that the organic functional groups that adsorb REE change with the stable isotope composition of SOC. This observation demonstrates the potential use of REE for tracing natural influences on behavior of SOC in the profiles of SOC‐rich soils.
Adsorption and Reactive Desorption on Metal–Organic Frameworks: A Direct Strategy for Lactic Acid Recovery
Authors: Stassin Timothée , Reinsch Helge , Van de Voorde Ben , Wuttke Stefan , Medina Dana D. , Stock Norbert , Bein Thomas , Ameloot Rob , De Vos Dirk
Published: November 2016

Biomass‐derived lactic acid (LA) is an important platform chemical towards the sustainable production of numerous materials. However, the fermentation process currently in use is limited by the difficult recovery of the LA product from the fermentation broth and results in the generation of stoichiometric amounts of gypsum waste. Herein, we show that metal–organic frameworks (MOFs) of the UiO‐66(Zr) type are effective adsorbents for the separation of LA from aqueous (buffer) solutions. These frameworks based on zirconium clusters and terephthalic acid derivatives display a tremendous uptake (up to 42 wt %) and a high affinity for LA. The latter can further be tuned by changing the hydrogen‐bonding properties of the functional groups present on the organic ligand. A Rietveld refinement disclosed the specific interaction of LA with the clusters of UiO‐66(Zr) and a preferential adsorption on open zirconium sites. Taking advantage of the catalytic activity of UiO‐66(Zr), desorption of LA was performed in alcohols to recover up to 73 % as ester. Applied to the recovery of LA, adsorption and reactive desorption offer a direct and gypsum‐free strategy as an alternative for the current multi‐step process.
Biorefining of Lignocellulosic Feedstock by a Modified Ammonia Fiber Expansion Pretreatment and Enzymatic Hydrolysis for Production of Fermentable Sugars
Authors: Kamm Birgit , Leiß Sebastian , Schönicke Petra , Bierbaum Matthias
Published: November 2016

Wheat straw was pretreated and afterwards enzymatically hydrolyzed using a modified ammonia fiber expansion (AFEX) process under different reaction conditions to produce fermentable sugars. Instead of liquid ammonia, aqueous ammonia (25 % w/v) was used to test its influence on the sugar concentration and yield of the sugars. It is shown that a protein extraction after the pretreatment can distinctly improve the result obtained for the enzymatic hydrolysis. This modified AFEX process using aqueous ammonia represents a simpler and less expensive variant of the AFEX process usually described in literature. Thus, the described process can be used for the primary refining of lignocellulosic feedstocks in the sense of a roadmap for biorefinery.
Hydrothermal Synthesis of ZnWO4 Hierarchical Hexangular Microstars for Enhanced Lithium‐Storage Properties
Authors: Shi Nianxiang , Xiong Shenglin , Wu Fangfang , Bai Jing , Chu Yanting , Mao Hongzhi , Feng Jinkui , Xi Baojuan
Published: November 2016

ZnWO4 hierarchical hexangular microstars (HHMs) composed of crossed microplatelets were synthesized by a two‐step hydrothermal reaction without using any surfactants. The homogeneous HHMs were characterized by TEM/SEM and XRD to reveal the structural features and crystallographic phase. On the basis of the analysis of the time‐dependent evolution of ZnWO4 HHMs, a mechanism of in‐situ formation and crystallographic fusion, wherein the morphology, components, and phase changed, is proposed to explain the formation process of 3D hexagonal structures. Furthermore, calcined ZnWO4 HHMs were evaluated as anode material for lithium‐ion batteries, and exhibited better rate capabilities and cycling performance than the as‐synthesized material. This can be attributed to the stabilized and highly crystalline structure as well as the synergic and interfacial effects between different metal ions, which relieve the volume change during the charge/discharge process and provide more active sites for lithium‐ion storage. The synthetic method and growth mechanism could be applied to design and synthesize other hierarchical structures.
Impact of Synthesis Parameters on the Formation of Defects in HKUST‐1
Authors: Zhang Wenhua , Kauer Max , Guo Penghu , Kunze Sebastian , Cwik Stefan , Muhler Martin , Wang Yuemin , Epp Konstantin , Kieslich Gregor , Fischer Roland A.
Published: November 2016

By employing various synthetic conditions, such as Cu(NO3)2·3H2O and Cu(BF4)2·6H2O as copper ion sources and different solvents, defect‐engineered analogues of metal–organic framework (MOF) [Cu3(BTC)2] (HKUST‐1; BTC = 1,3,5‐benzenetricarboxylate) with isophthalate (IP) incorporation (DEMOFs) were synthesised and characterised by powder XRD, SEM, IR spectroscopy, thermogravimetric analysis, NMR spectroscopy and N2 sorption. The results show that the choice of counter ions impacts the properties of the samples especially at high concentrations of IP. The combination of DMF and Cu(BF4)2·6H2O turns out to be superior for DEMOFs with IP incorporation up to 25 %. Ultrahigh‐vacuum IR spectra recorded upon CO adsorption together with the results of X‐ray photoelectron spectroscopic studies show the generation of coordinatively unsaturated Cu+ sites. The results suggest the presence of two different defect types, that is, missing‐linker defects and missing paddlewheels for high concentrations of IP.