bluuebunny/crossref_metadata_2025 huggingface dataset:
Antioxidants and Phenolic Secretion in Sugarcane Genotypes Shoots Culture
Authors: Ledo Ana Da Silva , Jenderek Maria M. , Ledo Carlos Alberto Da Silva , Ayala-Silva Tomas
Published: April 2018

Secretion of phenolic compounds is a major limitation for sugarcane in vitro shoot culture, causing a loss of regenerative capacity and subsequent cell death. In this study, micropropagation and phenolic secretion of four Saccharum genotypes were evaluated in presence of different antioxidants. Aseptic cultures of S. officinarum (PI 184794 and PI 88652), S. sinense (PI 29109) and S. robustum (UNK R65P35) were propagated on medium containing antioxidants, citric acid (100 mg/L), L-cysteine (100 mg/L), polyvynylpirrolidone (300 mg/L) and L-glutathione (50 mg/L) in two consecutive subculture cycles. Interaction between genotypes and antioxidants was significant in both cycles. All genotypes showed good shoot formation, shoot vigor and color, except in PI 88652 which had less shoot development in both the presence and absence of the antioxidants tested. PI 184794 displayed the highest shoot proliferation in the presence of citric acid, and UNK R65P35 produced more shoots per explant in the 2nd subculture. For S. sinense (PI 29109), in both subcultures, most shoots were observed in the presence of polyvynylpirrolidone. Medium discoloration due to phenolic secretion was reduced in the presence of citric acid and polyvynylpirrolidone. The type of secreted phenolic compounds differed with genotype as the Principal Component Analysis of cultivation media separated PI 88652 from PI 29109 and UKN R65P35. Phenolic compounds varied in composition and were secreted at various levels as a function of genotype and antioxidant type. Loadings plots indicated the genotype and antioxidant separations were broadly driven by flavonoid compounds.
Irrational Critique of Israel and Palestine: New Clothes for Traditional Prejudice?
Authors: Bulska Dominika , Winiewski Mikołaj
Published: April 2018

Among researchers of Antisemitism there is a relative consensus that at least some criticisms of Israel may indeed be a form of expressing Antisemitic prejudice in a more socially approved manner. However, the relations between Antisemitism and anti-Israelism are yet to be fully explained, especially since the issue is inextricably linked with the dynamic of the Israeli-Palestinian conflict. The two presented studies have two purposes: firstly, to measure Polish attitudes towards the Israeli-Palestinian conflict and, secondly, to establish the relationship between anti-Israelism and anti-Palestinism and more traditional types of prejudice, like Antisemitism and Islamophobia. In the first study (N = 301) we constructed a questionnaire of perception of the Israeli-Palestinian conflict with three subscales: Rational approach to conflict, extreme pro-Israeli opinions and extreme pro-Palestinian opinions. In the second study (N = 190) we found that both Antisemitism and Islamophobia predict the way Poles perceive the conflict between Israel and Palestine and beliefs in Jewish conspiracy seem to play the biggest role here. There is also evidence anti–Israelism is expressed not by criticizing Israel, but rather by expressing full support for Palestine. The questionnaire presented in this article may be treated as an indirect measure of Antisemitic prejudice, expressed in a more socially approved manner. Our findings may shed a new light on anti–Israelism and anti-Palestinism.
The “Szymanowski Clash”: Harmonic Conflict and Ambiguity in the Szymanowski Mazurkas
Authors: Bengtson Matthew
Published: April 2018

Among the greatest fascinations of Karol Szymanowski’s Mazurkas, op. 50 and op. 62, are their rich and sophisticated harmonic vocabulary. Many stylistic elements are combined together in this musical language, including pedal points, bagpipe fifths, modal mixture, and bitonality. The interplay of all these phenomena tends to destabilize functional harmonic relationships, leading to many instances of harmonic clashes by semitone, dubbed “Szymanowski clashes.” Considering this harmonic language through the lens of the Szymanowski clash can offer an understanding of this music that points to underlying compositional design and structural logic, while acting in accord with the listener’s perceptions of the musical surface.
La puissance technique de la médecine : des pistes de réflexion
Authors: Duplantie Andrée
Published: April 2018

Dans son livre Réflexion éthique et pratiques soignantes – Points de repère, Christian Gilioli relate l’évolution de la médecine et de l’éthique lesquelles entraînent des questionnements de natures philosophique, scientifique, technologique, sociale, économique et politique. Il propose des pistes de réflexions touchant la complexité de l’éthique contemporaine, dans un monde moderne toujours à la recherche du bonheur et de la santé et refusant le vieillissement et la souffrance.
Art + Bioéthique : quand la recherche en bioéthique quitte les murs de l’université
Authors: Couture Vincent , Bélisle-Pipon Jean-Christophe , Laliberté Maude
Published: April 2018

Comment engager le public dans une réflexion sur les enjeux éthiques de notre époque? Guidés par cette question, nous avons développé une plateforme d’échange avec la communauté sur des questions bioéthiques à travers une exposition artistique ainsi qu’une série d’activités de médiation culturelle et scientifique pour les adultes et les enfants. Ce dossier thématique dresse le compte-rendu de ce projet. Art + Bioéthique repose sur une stratégie interdisciplinaire et collaborative qui a amené six jeunes chercheurs en bioéthique à être jumelés à six artistes de la relève afin d’échanger et d’apporter un nouvel éclairage sur une variété d’enjeux éthiques liés à la santé. Ces duos artistes-chercheurs ont chacun développé une oeuvre et un essai sur un thème commun. Notre objectif était de décloisonner l’art et la recherche académique en bioéthique afin de créer des formes hybrides et inédites de diffusion, d’éducation, d’expérimentation et de rencontre. L’expression de la bioéthique à travers l’art constitue une façon innovatrice de transmettre l’aspect sensible de tant de questions éthiques touchant à la santé et au bien-être. À travers ses divers volets, Art+Bioéthique a su rejoindre plusieurs centaines de personnes et les engager dans une réflexion éthique sur des enjeux au coeur de notre société.
Faire dialoguer les cultures : rencontre entre la bioéthique et l’art contemporain
Authors: Cloutier Marianne
Published: April 2018

Cet essai aborde la rencontre entre les chercheurs en bioéthique et les artistes qui ont participé au projet Art + Bioéthique. La co-commissaire de l’exposition liée à ce projet présente ici la manière dont chaque artiste problématise un champ de recherche spécifique et en propose une interprétation personnelle à travers son oeuvre.
Pain, Disability, and Art: A Response to Verpaelst
Authors: Stahl Devan
Published: April 2018

Pain is inherently subjective and culturally mitigated and so it is difficult to measure and mitigate. Art creation has the ability to be therapeutic to persons in chronic pain.
Bre1 mediates the ubiquitination of histone H2B by regulating Lge1 stability
Authors: Kim Jueun , An Yu‐Kyoung , Park Shinae , Lee Jung‐Shin
Published: April 2018

Histone H2B ubiquitination mediated by the Rad6/Bre1 complex is crucial for regulating the stability and reassembly of the nucleosome. To understand the regulatory mechanisms of H2B ubiquitination, we explored proteins related to the Rad6/Bre1 complex. Interestingly, we observed that the stability of Lge1, reported to be a cofactor of Bre1, is greatly reduced in the absence of Bre1. The stability of Lge1 did require the middle fragment of Bre1 containing a coiled‐coil structure, but not its E3 ligase activity. Additionally, we found that Lge1 is involved in the ‘writing’ step of H2B ubiquitination. Our data suggest that Bre1 mediates H2B ubiquitination more precisely by maintaining the stability of Lge1 as well as through its role as a known E3 ligase.
Inkjet Printing of Multicolor Daylight Visible Opal Holography
Authors: Keller Kirill , Yakovlev Aleksandr V. , Grachova Elena V. , Vinogradov Alexandr V.
Published: April 2018

Inkjet printing of holography is a prospective technique for fabrication of anti‐counterfeiting devices and full‐color imaging. A method for production of multicolor opal holography using photonic colloidal crystals is presented. The method for direct printing of holograms on paper with transparent inks based on uniform polystyrene spheres with diameters 315, 450, and 550 nm, respectively, is presented. Inks are prepared and optimized by rheological parameters with the theory of Ohnesorge numbers. Opal‐like structures are formed on a silicon wafer, glass slide, and glossy photo paper under variation temperatures of drying and different number of layers. Drops morphology and effect on optical properties are profoundly studied. The implementation of Fourier transform of the radial distribution function for calculation of relative value of ordering of the colloidal spheres in the printed drop which allows estimating the influence of printing defects and coffee‐ring on total particle order in the printed drop is reported for the first time. The received data have a direct applied value and can be used in future printing technologies.
Merging Biology and Solid‐State Lighting: Recent Advances in Light‐Emitting Diodes Based on Biological Materials
Authors: Fresta Elisa , Fernández‐Luna Verónica , Coto Pedro B. , Costa Rubén D.
Published: April 2018

Solid‐state lighting (SSL) is one of the biggest achievements of the 20th century. It has completely changed our modern life with respect to general illumination (light‐emitting diodes), flat devices and displays (organic light‐emitting diodes), and small labeling systems (light‐emitting electrochemical cells). Nowadays, it is however mandatory to make a transition toward green, sustainable, and equally performing lighting systems. In this regard, several groups have realized that the actual SSL technologies can easily and efficiently be improved by getting inspiration from how natural systems that manipulate light have been optimized over millennia. In addition, various natural and biocompatible materials with suitable properties for lighting applications have been used to replace expensive and unsustainable components of current lighting devices. Finally, SSL has also started to revolutionize the biomedical field with the achievement of efficient implantable lighting systems. Herein, the‐state‐of‐art of (i) biological materials for lighting devices, (ii) bioinspired concepts for device designs, and (iii) implantable SSL technologies is summarized, highlighting the perspectives of these emerging fields.
Light‐Driven Electrohydrodynamic Instabilities in Liquid Crystals
Authors: Zhan Yuanyuan , Schenning Albertus P. H. J. , Broer Dirk J. , Zhou Guofu , Liu Danqing
Published: April 2018

The induction of electrohydrodynamic instabilities in nematic liquid crystals through light illumination are reported. For this purpose, a photochromic spiropyran is added to the liquid crystal mixture. When an electrical field is applied in the absence of UV light, the homeotropic liquid crystal reorients perpendicular to the electrical field driven by its negative dielectric anisotropy. Upon exposure to UV light, the nonionic spiropyran isomerizes to the zwitterionic merocyanine form inducing electrohydrodynamic instabilities which turns the cell from transparent into highly scattering. The reverse isomerization to closed‐ring spiropyran form occurs thermally or under visible light, which stops the electrohydrodynamic instabilities and the cell becomes transparent again. It is demonstrated that the photoionic electrohydrodynamic instabilities can be used for light regulation. Local exposure, either to drive the electrohydrodynamics or to remove them enables the formation of colored images.
Ferromagnetic Nanoparticle–Assisted Polysulfide Trapping for Enhanced Lithium–Sulfur Batteries
Authors: Gao Zan , Schwab Yosyp , Zhang Yunya , Song Ningning , Li Xiaodong
Published: April 2018

The lithium–sulfur (Li–S) battery is a promising candidate for next‐generation high‐density energy storage devices because of its ultrahigh theoretical energy density and the natural abundance of sulfur. However, the practical performance of the sulfur cathode is plagued by fast capacity decay and poor cycle life, both of which can be attributed to the intrinsic dissolution/shuttling of lithium polysulfides. Here, a new built‐in magnetic field–enhanced polysulfide trapping mechanism is discovered by introducing ferromagnetic iron/iron carbide (Fe/Fe3C) nanoparticles with a graphene shell (Fe/Fe3C/graphene) onto a flexible activated cotton textile (ACT) fiber to prepare the ACT@Fe/Fe3C/graphene sulfur host. The novel trapping mechanism is demonstrated by significant differences in the diffusion behavior of polysulfides in a custom‐designed liquid cell compared to a pure ACT/S cathode. Furthermore, a cell assembled using the ACT@Fe/Fe3C/S cathode exhibits a high initial discharge capacity of ≈764 mAh g−1, excellent rate performance, and a remarkably long lifespan of 600 cycles using ACT@Fe/Fe3C/S (whereas only 100 cycles can be achieved using pure ACT/S). The new magnetic field–enhanced trapping mechanism provides not only novel insight but unveils new possibilities for mitigating the “shuttle effect” of polysulfides thereby promoting the practical applications of Li–S batteries.
Water‐Dispersible Polydopamine‐Coated Nanofibers for Stimulation of Neuronal Growth and Adhesion
Authors: Sieste Stefanie , Mack Thomas , Synatschke Christopher V. , Schilling Corinna , Meyer zu Reckendorf Christopher , Pendi Laura , Harvey Sean , Ruggeri Francesco S. , Knowles Tuomas P. J. , Meier Christoph , Ng David Y. W. , Weil Tanja , Knöll Bernd
Published: April 2018

Hybrid nanomaterials have shown great potential in regenerative medicine due to the unique opportunities to customize materials properties for effectively controlling cellular growth. The peptide nanofiber‐mediated auto‐oxidative polymerization of dopamine, resulting in stable aqueous dispersions of polydopamine‐coated peptide hybrid nanofibers, is demonstrated. The catechol residues of the polydopamine coating on the hybrid nanofibers are accessible and provide a platform for introducing functionalities in a pH‐responsive polymer analogous reaction, which is demonstrated using a boronic acid modified fluorophore. The resulting hybrid nanofibers exhibit attractive properties in their cellular interactions: they enhance neuronal cell adhesion, nerve fiber growth, and growth cone area, thus providing great potential in regenerative medicine. Furthermore, the facile modification by pH‐responsive supramolecular polymer analog reactions allows tailoring the functional properties of the hybrid nanofibers in a reversible fashion.
Porous Microrod Arrays Constructed by Carbon‐Confined NiCo@NiCoO2 Core@Shell Nanoparticles as Efficient Electrocatalysts for Oxygen Evolution
Authors: Xu Han , Shi Zi‐Xiao , Tong Ye‐Xiang , Li Gao‐Ren
Published: April 2018

The study of cost‐efficient and high‐performance electrocatalysts for oxygen evolution reaction (OER) has attracted much attention. Here, porous microrod arrays constructed by carbon‐confined NiCo@NiCoO2 core@shell nanoparticles (NiCo@NiCoO2/C PMRAs) are fabricated by the reductive carbonization of bimetallic (Ni, Co) metal–organic framework microrod arrays (denoted as NiCo‐MOF MRAs) and subsequent controlled oxidative calcination. They successfully combine the desired merits including large specific surface areas, high conductivity, and multiple electrocatalytic active sites for OER. In addition, the oxygen vacancies in NiCo@NiCoO2/C PMRAs significantly improve the conductivity of NiCoO2 and accelerate the kinetics of OER. The above advantages obviously enhance the electrocatalytic performance of NiCo@NiCoO2/C PMRAs. The experimental results demonstrate that the NiCo@NiCoO2/C PMRAs as electrocatalysts exhibit high catalytic activity, low overpotential, and high stability for OER in alkaline media. The strategy reported will open up a new route for the fabrication of porous bimetallic composite electrocatalysts derived from MOFs with controllable morphology for electrochemical energy conversion devices.
Magnetoactive Acoustic Metamaterials
Authors: Yu Kunhao , Fang Nicholas X. , Huang Guoliang , Wang Qiming
Published: April 2018

Acoustic metamaterials with negative constitutive parameters (modulus and/or mass density) have shown great potential in diverse applications ranging from sonic cloaking, abnormal refraction and superlensing, to noise canceling. In conventional acoustic metamaterials, the negative constitutive parameters are engineered via tailored structures with fixed geometries; therefore, the relationships between constitutive parameters and acoustic frequencies are typically fixed to form a 2D phase space once the structures are fabricated. Here, by means of a model system of magnetoactive lattice structures, stimuli‐responsive acoustic metamaterials are demonstrated to be able to extend the 2D phase space to 3D through rapidly and repeatedly switching signs of constitutive parameters with remote magnetic fields. It is shown for the first time that effective modulus can be reversibly switched between positive and negative within controlled frequency regimes through lattice buckling modulated by theoretically predicted magnetic fields. The magnetically triggered negative‐modulus and cavity‐induced negative density are integrated to achieve flexible switching between single‐negative and double‐negative. This strategy opens promising avenues for remote, rapid, and reversible modulation of acoustic transportation, refraction, imaging, and focusing in subwavelength regimes.
Bioinspired Hydrogel Interferometer for Adaptive Coloration and Chemical Sensing
Authors: Qin Meng , Sun Mo , Bai Ruobing , Mao Yiqi , Qian Xiaoshi , Sikka Dipika , Zhao Yuan , Qi Hang Jerry , Suo Zhigang , He Ximin
Published: April 2018

Living organisms ubiquitously display colors that adapt to environmental changes, relying on the soft layer of cells or proteins. Adoption of soft materials into an artificial adaptive color system has promoted the development of material systems for environmental and health monitoring, anti‐counterfeiting, and stealth technologies. Here, a hydrogel interferometer based on a single hydrogel thin film covalently bonded to a reflective substrate is reported as a simple and universal adaptive color platform. Similar to the cell or protein soft layer of color‐changing animals, the soft hydrogel layer rapidly changes its thickness in response to external stimuli, resulting in instant color change. Such interference colors provide a visual and quantifiable means of revealing rich environmental metrics. Computational model is established and captures the key features of hydrogel stimuli‐responsive swelling, which elucidates the mechanism and design principle for the broad‐based platform. The single material–based platform has advantages of remarkable color uniformity, fast response, high robustness, and facile fabrication. Its versatility is demonstrated by diverse applications: a volatile‐vapor sensor with highly accurate quantitative detection, a colorimetric sensor array for multianalyte recognition, breath‐controlled information encryption, and a colorimetric humidity indicator. Portable and easy‐to‐use sensing systems are demonstrated with smartphone‐based colorimetric analysis.
Are rates of species diversification and body size evolution coupled in the ferns?
Authors: Testo Weston L. , Sundue Michael A.
Published: April 2018

Premise of the Study

Understanding the relationship between phenotypic evolution and lineage diversification is a central goal of evolutionary biology. To extend our understanding of the role morphological evolution plays in the diversification of plants, we examined the relationship between leaf size evolution and lineage diversification across ferns.

Methods

We tested for an association between body size evolution and lineage diversification using a comparative phylogenetic approach that combined a time‐calibrated phylogeny and leaf size data set for 2654 fern species. Rates of leaf size change and lineage diversification were estimated usingBAMM, and rate correlations were performed for rates obtained for all families and individual species. Rates and patterns of rate–rate correlation were also analyzed separately for terrestrial and epiphytic taxa.

Key Results

We find no significant correlation between rates of leaf area change and lineage diversification, nor was there a difference in this pattern when growth habit is considered. Our results are consistent with the findings of an earlier study that reported decoupled rates of body size evolution and diversification in the Polypodiaceae, but conflict with a recent study that reported a positive correlation between body size evolution and lineage diversification rates in the tree fern family Cyatheaceae.

Conclusions

Our findings indicate that lineage diversification in ferns is largely decoupled from shifts in body size, in contrast to several other groups of organisms. Speciation in ferns appears to be primarily driven by hybridization and isolation along elevational gradients, rather than adaptive radiations featuring prominent morphological restructuring. The exceptional diversity of leaf morphologies in ferns appears to reflect a combination of ecophysiological constraints and adaptations that are not key innovations.
The impact of weather, road surface, time‐of‐day, and light conditions on severity of bicycle‐motor vehicle crash injuries
Authors: Asgarzadeh Morteza , Fischer Dorothee , Verma Santosh K. , Courtney Theodore K. , Christiani David C.
Published: April 2018

Background

This study examined whether environmental variables including weather, road surface, time‐of‐day, and light conditions were associated with the severity of injuries resulting from bicycle‐motor vehicle crashes.

Methods

Using log‐binomial regressions, we analyzed 113 470 police reports collected between 2000 and 2014 in four U.S. states with environmental and injury severity information. “Severe” injuries included fatal and incapacitating injuries, and “non‐severe” included non‐incapacitating, possible or no‐injuries.

Results

Light condition was significantly associated with the injury severity to the bicyclist with more severe injuries at dawn (RR = 1.62 [95%CI 1.35‐1.94]) and during darkness (both lighted and unlighted roads: 1.32 [1.24‐1.40], respectively, 1.57 [1.41‐1.76]) as compared to daylight. In these conditions of low visibility, risk was further increased during early morning hours before 7 am (1.61 [1.22‐2.13]).

Conclusions

Crashes in low light conditions and during early morning hours are more likely to result in higher injury severity.
Rubinstein–Taybi syndrome: New neuroradiological and neuropsychiatric insights from a multidisciplinary approach
Authors: Ajmone Paola F. , Avignone Sabrina , Gervasini Cristina , Giacobbe Antonella , Monti Fedrico , Costantino Antonella , Esposito Susanna , Marchisio Paola , Triulzi Fabio , Milani Donatella
Published: April 2018

Rubinstein–Taybi syndrome is a rare, autosomal dominant, plurimalformative disorder that is clinically characterized by intellectual disability and a wide spectrum of congenital anomalies; facial dysmorphisms are typical, and broad thumbs and great toes are particularly distinctive. Its genetic basis is only partially known, with a detection rate of approximately 65–70%; specifically, microdeletions or mutations in the CREBBP or EP300 genes can be found. Much is known about its clinical features and health‐care protocols, but some areas of clinical knowledge are currently unsolved. In particular, few efforts have been made until now to understand the variability in the neuropsychological and neurobehavioral profile and to deepen knowledge of the neuroradiological malformative pattern. Consequently, little is known about the possible genotype‐phenotype correlations of these issues. Here, we report clinical and genetic data from a cohort of 23 RSTS Italian patients. The most common features in brain magnetic resonance imaging (MRI) were dysmorphic aspects of the corpus callosum (73.6%) with or without minor dysmorphisms of cerebellar vermis, periventricular posterior white matter hyperintensity, and other less common anomalies. The most interesting feature on the whole spine MRI scans was the tendency for a low‐lying conus medullaris without terminal filum thickening. These data will help to improve neuropsychiatric and neuroradiological knowledge and highlight specific genotype‐phenotype correlations.
Social and ecological correlates of space use patterns in Bwindi mountain gorillas
Authors: Seiler Nicole , Boesch Christophe , Stephens Colleen , Ortmann Sylvia , Mundry Roger , Robbins Martha M.
Published: April 2018

Space use patterns determine access to resources necessary for survival and reproduction. Although it is recognized that the interplay between social and ecological variables shapes spacing patterns, few studies in group‐living animals have simultaneously assessed their importance in a comprehensive approach using different spatiotemporal space use measures. In territorial species, such patterns are strongly determined by between‐group competition, but its impact in non‐territorial species is poorly understood. To better understand the role of social and ecological variables in non‐territorial mountain gorillas (Gorilla beringei beringei), we simultaneously evaluated the impact of between‐group competition (local gorilla population density and frequency of intergroup encounters) and within‐group competition (group size) on space use patterns in 13 gorilla groups in Bwindi Impenetrable National Park, Uganda, while also examining variation in food availability (herbaceous food availability and level of frugivory). We found evidence of between‐group competition, indicated by a decline of both monthly home range size and frequency of revisits to each part of the home range as the local gorilla population density increased and by an increase in daily travel distance on days when intergroup encounters occurred. Within‐group feeding competition was inferred by a decrease in the frequency of revisits as group size increased. Lastly, food availability influenced the gorillas' spacing patterns, as indicated by a decline in monthly home range size as herbaceous food availability increased and by an increase in daily travel distance as the degree of frugivory increased. In sum, our results suggest that Bwindi gorillas adapted their space use according to the constraints of intraspecific competition and the availability of food resources. We provide some of the first evidence of between‐group competition influencing spacing patterns in a non‐territorial species. This study suggests a gradient between territoriality and non‐territoriality, along which the level of between‐group competition varies.
Insights into the Crystallization and Structural Evolution of Glycine Dihydrate by In Situ Solid‐State NMR Spectroscopy
Authors: Cerreia Vioglio Paolo , Mollica Giulia , Juramy Marie , Hughes Colan E. , Williams P. Andrew , Ziarelli Fabio , Viel Stéphane , Thureau Pierre , Harris Kenneth D. M.
Published: April 2018

In situ solid‐state NMR spectroscopy is exploited to monitor the structural evolution of a glycine/water glass phase formed on flash cooling an aqueous solution of glycine, with a range of modern solid‐state NMR methods applied to elucidate structural properties of the solid phases present. The glycine/water glass is shown to crystallize into an intermediate phase, which then transforms to the β polymorph of glycine. Our in situ NMR results fully corroborate the identity of the intermediate crystalline phase as glycine dihydrate, which was first proposed only very recently.
Electrooxidative Rhodium‐Catalyzed C−H/C−H Activation: Electricity as Oxidant for Cross‐Dehydrogenative Alkenylation
Authors: Qiu Youai , Kong Wei‐Jun , Struwe Julia , Sauermann Nicolas , Rogge Torben , Scheremetjew Alexej , Ackermann Lutz
Published: April 2018

Rhodium(III) catalysis has enabled a plethora of oxidative C−H functionalizations, which predominantly employ stoichiometric amounts of toxic and/or expensive metal oxidants. In contrast, we herein describe the first electrochemical rhodium‐catalyzed C−H activation that avoids hazardous chemical oxidants. Environmentally benign twofold C−H/C−H functionalizations were accomplished with weakly coordinating benzoic acids and benzamides, employing electricity as the terminal oxidant and generating H2 as the sole byproduct.
Synthesis, Structure, and Anion Binding Properties of Electron‐Deficient Tetrahomocorona[4]arenes: Shape Selectivity in Anion–π Interactions
Authors: Liu Han‐Bin , Zhang Qian , Wang Mei‐Xiang
Published: April 2018

Tetrahomocorona[2]arene[2]tetrazines were constructed by means of a fragment coupling strategy based on nucleophilic aromatic substitution reaction starting from 3,6‐dichlorotetrazine and o‐, m‐, and p‐bis(hydroxymethyl)benzenes. The unprecedented macrocycles gave rectangular box‐like cavities with tunable cavity sizes and deficient electronic properties depending on the substitution pattern of phenylene. Due to anion–π interactions, they formed complexes selectively with azide and thiocyanate owing to complementary shapes between host and guest.
Near‐Infrared Sensitized Photoinduced Atom‐Transfer Radical Polymerization (ATRP) with a Copper(II) Catalyst Concentration in the ppm Range
Authors: Kütahya Ceren , Schmitz Christian , Strehmel Veronika , Yagci Yusuf , Strehmel Bernd
Published: April 2018

NIR‐sensitized photoinduced atom‐transfer radical polymerization (ATRP) is possible by using ppm of CuII/tris(2‐pyridylmethyl)amine (TPMA) as the catalyst, a polymethine as the photosensitizer, and α‐bromophenylacetate as the alkyl halide initiator. Among the polymethines investigated with cationic, zwitterionic, or anionic structures, only the zwitterionic 2 exhibited sensitization activity under NIR light at room temperature resulting in the formation of polymers with controlled molecular weight characteristics and functionalities. The barbital group placed at the meso‐position of 2 caused the activity in this photo‐ATRP framework. The chain‐end fidelity of the polymers was confirmed by chain extension and block copolymerization experiments. The polymerization system exhibits high photostability under NIR light exposure and irradiation dependency as demonstrated by light on/off experiments.
Diferrocenylmercury‐Bridged Diphosphine: A Chiral, Ambiphilic, and Redox‐Active Bidentate Ligand
Authors: Tagne Kuate Alain C. , Lalancette Roger A. , Bannenberg Thomas , Jäkle Frieder
Published: April 2018

A diphosphine chelate ligand with a wide and flexible bite angle, a unique stereochemical environment, and redox‐active and ambiphilic character is reported. Initially generated as its HgCl2 complex by reaction of 1,2‐fc(PPh2)(SnMe3) (fc=ferrocenediyl) with HgCl2 in acetone, treatment with [n‐Bu4N]CN readily liberates the free chiral bidentate ligand. An intermolecular ClHg−Cl→Hgfc2 (2.9929(13) Å) interaction that is unprecedented in ambiphilic ligand chemistry is seen in the solid structure of Hg(fcPPh2)2⋅HgCl2 where the bridging mercury atom acts as a σ‐acceptor. Furthermore, a bis‐[Rh(COD)Cl] complex is introduced, which displays relatively short Rh⋅⋅⋅Hg contacts of 3.4765(5) and 3.4013(1) Å. Wiberg indices of 0.12 are determined for these Rh⋅⋅⋅Hg interactions and an AIM analysis reveals bond paths with an electron density ρ(r) of 1.2×10−2 and 1.4×10−2 e/a03 at the bond critical points.
Design and synthesis of novel thiourea metal complexes with controllable antibacterial properties
Authors: Rakhshani Sajjad , Rezvani Ali Reza , Dušek Michal , Eigner Václav
Published: April 2018

A new bidentate O,S donor thiourea ligand (L1), namely N‐(2‐hydroxyethyl)‐N′‐2‐chlorobenzoylthiourea, and its oxazolidine derivative (L2) were synthesized. Derivative L2 was used for the preparation of Ni(L2)2 and Cu(L2)2 complexes. The compounds were investigated using X‐ray crystallography and Fourier transform infrared, 1H NMR and UV–visible spectroscopies. Single‐crystal X‐ray analysis showed strong hydrogen bonding interactions between carbonyl oxygen and N(10) ─ H in the L1 ligand. In addition, the antibacterial activities of these compounds were evaluated against Gram‐positive and Gram‐negative bacteria, measured using the colony count method. The Cu(L2)2 complex exhibited a significant antibacterial activity while the activity of the other compounds was much lower. Finally, the relationship between the structure and antibacterial properties of these compounds was investigated using highest occupied and lowest unoccupied molecular orbital energies calculated by density functional theory method based on the 6‐31G*/LANL2DZ basis set.
POSS nanocrosslinked poly (ethylene glycol) hydrogel as hybrid material support for silver nanocatalyst
Authors: Kazeminava Fahimeh , Arsalani Nasser , Akbari Ali
Published: April 2018

Silver nanoparticles supported on polyhedral oligomeric silsesquioxane (OA‐POSS) nanocrosslinked poly (ethylene glycol)‐based hydrogels (PEG600‐POSS/Ag NPs) as novel nanohybrid catalysts were synthesized for the first time. The as‐prepared nanohybrid hydrogels were fully characterized by FT‐IR, SEM, EDX, XRD, TEM and TGA. PEG600‐POSS/Ag NPs exhibited excellent catalytic performance for the reduction of 4‐nitrophenol (4‐NP) to 4‐aminophenol (4‐AP) in water at room temperature in the presence of borohydride.
Synthesis, structural and chemosensitivity studies of arene d6 metal complexes having N‐phenyl‐N´‐(pyridyl/pyrimidyl)thiourea derivatives
Authors: Adhikari Sanjay , Hussain Omar , Phillips Roger M. , Kaminsky Werner , Kollipara Mohan Rao
Published: April 2018

The d6 metal complexes of thiourea derivatives were synthesized to investigate its cytotoxicity. Treatment of various N‐phenyl‐N´ pyridyl/pyrimidyl thiourea ligands with half‐sandwich d6 metal precursors yielded a series of cationic complexes. Reactions of ligand (L1‐L3) with [(p‐cymene)RuCl2]2 and [Cp*MCl2]2 (M = Rh/Ir) led to the formation of a series of cationic complexes bearing general formula [(arene)M(L1)к2(N,S)Cl]+, [(arene)M(L2)к2(N,S)Cl]+ and [(arene)M(L3)к2(N,S)Cl]+ [arene = p‐cymene, M = Ru (1, 4, 7); Cp*, M = Rh (2, 5, 8); Cp*, Ir (3, 6, 9)]. These compounds were isolated as their chloride salts. X‐ray crystallographic studies of the complexes revealed the coordination of the ligands to the metal in a bidentate chelating N,S‐ manner. Further the cytotoxicity studies of the thiourea derivatives and its complexes evaluated against HCT‐116 (human colorectal cancer), MIA‐PaCa‐2 (human pancreatic cancer) and ARPE‐19 (non‐cancer retinal epithelium) cancer cell lines showed that the thiourea ligands displayed no activity. Upon complexation however, the metal compounds possesses cytotoxicity and whilst potency is less than cisplatin, several complexes exhibited greater selectivity for HCT‐116 or MIA‐PaCa‐2 cells compared to ARPE‐19 cells than cisplatin in vitro. Rhodium complexes of thiourea derivatives were found to be more potent as compared to ruthenium and iridium complexes.
Crystal packing, vibrational studies, DFT calculations of a new hybrid nickel (II)‐complex and its application in Heck and Sonogashira cross‐ coupling reactions
Authors: Jaballi Rim , Maalej Wassim , Atoui Dhieb , Feki Habib , Ben Salem Ridha , Elaoud Zakaria
Published: April 2018

We particularly investigate a new material [Ni(C12H12N2)(H2O)4]SO4 that it was hydrothermally synthesized by reaction of 5,5’‐dimethyl‐2,2’‐bipyridne, denoted (dmbpy), metal salt and sulfuric acid. The large crystals are characterized by X‐ray single crystal diffraction, infrared, Raman spectroscopy and DFT calculation. The thermogravimetric analysis indicated that the dehydration occurs in two steps, leading to an anhydrous compound. At room temperature, the complex crystallises in the centrosymmetric space group P21/c with the following parameters a = 9.492 (7) Å, b = 9.539 (7) Å, c = 18.411 (1) Å,

β =102.616 (1)°, V = 1626.8 (2) Å3 and Z = 4. The asymmetric unit contains one free SO42‐counter‐ion and [Ni(dmbpy)(H2O)4]2+ complex cation. The crystal structure of the complex is built up from infinite parallel two‐dimensional planes, containing all the components of the structure and perpendicular to the axis b. The aqua ligands are connected to the sulfate anion via O‐H…O hydrogen bonds that stabilize the three‐dimensional network.

The catalytic activity of the complex was examined in the coupling reactions of Heck and Sonogashira in the presence of different bases in various organic solvents under ultrasonic irradiation. The obtained results show that this type of complex can be considered as an effective catalyst for these coupling reactions. The ultrasonic activation results the encouraging yields for a short period of time: 30‐45 min.
Characteristic features of thermoluminescence in neodymium‐doped gallium sulfide
Authors: Guler I. , Isik M. , Ahmedova F. , Guseinov A. , Gasanly N.
Published: April 2018

The thermoluminescence (TL) of neodymium‐doped gallium sulfide (GaS:Nd) single crystals was measured from 10 K to room temperature with various heating rates between 0.2 and 1.0 K/sec. Two peaks centered at 70.9 K and 116.0 K were observed when using a heating rate of 0.8 K/sec. Initial rise and curve fitting methods were used to obtain information on trap activation energies. Activation energies of 94 and 216 meV were found for two analyzable peaks. The heating rate dependencies of TL intensities revealed that one of the observed peaks showed normal behavior according to the one trap‐one recombination model, whereas the other model showed anomalous heating rate behavior. TL experiments were also carried out at different illumination temperatures from 10 to 32 K; maximum peak temperature remained almost the same at various illumination temperatures. This behavior indicated that the revealed trapping centers are single, discrete levels. The TL glow curves of undoped GaS crystals were also investigated and the effect of Nd doping on the TL characteristics of crystals is discussed in the manuscript.
Transient Expression of Human Cytochrome P450s 2D6 and 3A4 in Nicotiana benthamiana Provides a Possibility for Rapid Substrate Testing and Production of Novel Compounds
Authors: Sheludko Yuriy V. , Gerasymenko Iryna M. , Warzecha Heribert
Published: April 2018

Employment of transient expression of foreign genes for bioconversion of pharmaceutically valuable low‐molecular‐weight compounds, including plant secondary metabolites, is an enticing trend still scantily explored in plant biotechnology. In the present work, an efficient protocol for rapid assessment of synthetic and plant‐derived metabolites as potential substrates for human P450s (CYP2D6 and CYP3A4) via Agrobacterium‐mediated transient expression in Nicotiana benthamiana is put forth. Animal P450s with broad substrate specificity are promising candidates for transformation of diverse metabolites. The efficiency of P450s in heterologous surroundings is not always satisfactory and depends on the availability of an associated electron‐transfer enzyme. Plants represent an attractive assortment of prospective hosts for foreign P450s expression. The optimal composition of genetic blocks providing the highest transient expression efficiency is designed, an effective substrate administration scheme is validated, and biological activity of the investigated P450s against loratadine and several indole alkaloids with different molecular scaffold structures is tested. A novel indole alkaloid, 11‐hydroxycorynanthine, is isolated from N. benthamiana plants transiently expressing CYP2D6 and supplemented with corynanthine, and its structure was elucidated. The proposed technique might be of value in realization of combinatorial biosynthesis concept comprising the junction of heterologous enzymes and substrates in different metabolic surroundings.
Determination of four antiepileptic drugs in plasma using ultra‐performance liquid chromatography with mass detection technique
Authors: Hassib Sonia T. , Hashem Hanaa M.A. , Mahrouse Marianne A. , Mostafa Eman A.
Published: April 2018

Status epilepticus (SE) is considered the second most frequent neurological emergency. Its therapeutic management is performed using sequential antiepileptic drug regimens. Diazepam (DIA), midazolam (MID), phenytoin (PHT) and phenobarbital (PB) are four drugs of different classes used sequentially in the management of SE. A sensitive, selective, accurate and precise method was developed and validated for simultaneous determination of the four antiepileptic drugs in human plasma. Their separation and quantification were achieved using ultra‐performance liquid chromatography (UPLC) with mass detection using carbamazepine as internal standard (IS). For the first three drugs and the IS, UPLC–MS/MS with electrospray ionization working in multiple reaction monitoring mode was used at the following transitions: m/z 285 → 193 for DIA; m/z 326 → 291 for MID; m/z 253 → 182 for PHT; and m/z 237 → 194, 237 → 192 for IS. For the fourth drug (PB), a molecular ion peak of PB [M + H] + at m/z 233 was used for its quantitation. The method was linear over concentration ranges 5–500 ng/mL for DIA and MID and 0.25–20 μg/mL for PHT and PB. Bioanalytical validation of the developed method was carried out according to European Medicines Agency guidelines. The developed method can be applied for routine drug analysis, therapeutic drug monitoring and bioequivalence studies.
Too little, too much or just right? Goldilocks revisited…
Authors: Sharma Rahul , Henry Timothy D.
Published: April 2018

Key Points

This study highlights the low rates of UCA in OHCA patients in a real‐world setting

Presentation with ST elevation, shockable rhythm and history of CAD were more likely to result in UCA for OHCA patients

Further studies are required to help create a systematic and standardized approach to UCA in OHCA patients
Reverse Solvatochromism of Imine Dyes Comprised of 5‐Nitrofuran‐2‐yl or 5‐Nitrothiophen‐2‐yl as Electron Acceptor and Phenolate as Electron Donor
Authors: de Melo Carlos E. A. , Nicoleti Celso R. , Rezende Marcos C. , Bortoluzzi Adailton J. , da S. Heying Renata , da S. Oliboni Robson , Caramori Giovanni F. , Machado Vanderlei G.
Published: April 2018

Eight compounds with phenols as electron‐donating groups and 5‐nitrothiophen‐2‐yl or 5‐nitrofuran‐2‐yl acceptor moieties in their molecular structures were synthesized. The crystalline structures of six compounds were obtained. Their corresponding phenolate dyes were studied in 29 solvents and the data showed that in all cases a reverse solvatochromism occurred. The results are explained in terms of the ability of the medium to stabilize the electronic ground and excited states of the probes to different extents. The frontier molecular orbitals were analyzed for the protonated and deprotonated forms of the compounds. The calculated geometries are in agreement with the X‐ray structures determined for the compounds and it was verified that after their deprotonation an increase in the electron delocalization occurs. Radial distribution functions were calculated for the dyes in water and n‐hexane to analyze different solvation patterns resulting from the interaction of the solvents with the dyes. Data obtained by using the Catalán multiparameter equation revealed that the medium acidity is responsible for hypsochromic shifts, whereas the solvent basicity, polarizability, and dipolarity contributed to bathochromic shifts of the solvatochromic band of these dyes. Two model “hybrid cyanine” dyes were used in the design of simple experiments to demonstrate that the solvatochromic behavior of these dyes in solution can be tuned with careful consideration of the properties of the medium.
Copper Promoted Regio‐ and Stereoselective Aminochlorination of Alkynes and Alkenes with NFSI
Authors: Wang Weilin , Liu Lingyan , Chang Weixing , Li Jing
Published: April 2018

A simple and rapid copper‐promoted aminochlorination of unactivated alkynes and alkenes with N‐fluorobenzenesulfonimide (NFSI) was developed. Two series of chloroenamines and chloroamines were obtained in good to high yields. The chlorinated enamines could be obtained in a single E configuration. This reaction involved a radical process and the CuCl2 acted as the Cl source and NFSI as the N source.
Development of an Efficient Dual‐Action GST‐Inhibiting Anticancer Platinum(IV) Prodrug
Authors: Lee Keefe Guang Zhi , Babak Maria V. , Weiss Andrea , Dyson Paul J. , Nowak‐Sliwinska Patrycja , Montagner Diego , Ang Wee Han
Published: April 2018

The cytotoxicity of cisplatin (cDDP) is enhanced when co‐administered with ethacrynic acid (EA), a glutathione S‐transferase (GST) inhibitor. A PtIV–EA conjugate containing a cDDP core and two axial ethacrynate ligands (compound 1) was shown to be an excellent inhibitor of GST, but did not readily release a PtII species to exert a synergistic cytotoxic effect. In this study, a redesigned PtIV construct composed of a cDDP core with one axial ethacrynate ligand and one axial hydroxido ligand (compound 2) was prepared and shown to overcome the limitations of compound 1. The EA ligand in 2 is readily released in vitro together with a cytotoxic PtII species derived from cisplatin, working together to inhibit cell proliferation in cDDP‐resistant human ovarian cancer cells. The in vitro activity translates well in vivo with 2, showing effective (∼80 %) inhibition of tumor growth in a human ovarian carcinoma A2780 tumor model, while showing considerably lower toxicity than cisplatin, thus validating the new design strategy.
Cancer drug shortages: Awareness and perspectives from a representative sample of the US population
Authors: Frosch Zachary A. K. , Cronin Angel M. , Gagne Joshua J. , Teschke Maxwell P. , Gray Stacy W. , Abel Gregory A.
Published: April 2018

BACKGROUND

Although cancer drug shortages are a persistent problem in oncology, little is known about the awareness and perspectives of the US population with respect to shortages.

METHODS

In 2016, we administered a 13‐item cross‐sectional survey to 420 respondents who were randomly selected from an online, probability‐based sample demographically representative of the adult US population with respect to sex, age, race/ethnicity, education, geography, and income. Analyses applied poststratification sampling weights to draw national inferences.

RESULTS

Overall, 16% of respondents reported being aware of drug shortages. Those with a personal history of cancer were more likely to be aware (31% vs 14% [P = .03]). In the overall cohort, most reported wanting to be informed about a substitution due to shortage: 87% and 82% for major or minor differences in efficacy, and 87% and 83% for major or minor differences in side effects. Most also reported they would transfer care to avoid a substitution: 72% for major differences in efficacy, and 61% for major differences in side effects. Black respondents, the uninsured, the unemployed, those with lower income, and the less well‐educated were all less likely to report that they would transfer care to avoid major differences in efficacy (all P < .05).

CONCLUSION

These data suggest that the US population is largely unaware of cancer drug shortages. Moreover, if being treated for cancer, most people would want to know about drug substitutions, even if it were to result in only minor differences in efficacy or side effects. With more significant differences, many would transfer care. Cancer 2018;124:2205‐11. © 2018 American Cancer Society.