bluuebunny/crossref_metadata_2025_split huggingface dataset:
Palladium‐Catalyzed Chemoselective Switch: Synthesis of a New Class of Indenochromenes and Pyrano[2,3‐c]carbazoles
Authors: Reddy K. Ranjith , Kannaboina Prakash , Das Parthasarathi 
Published: January 2017

AbstractA new method has been developed for the divergent synthesis of two different pyran‐annulated polyheterocycles, indeno[1,2,3‐de]chromenes, and pyrano[2,3‐c]carbazoles from a common intermediate. The indeno[1,2,3‐de]chromenes class of compounds has been synthesized by using Oxone as a terminal oxidant through a Pd‐catalyzed cross‐dehydrogenative coupling reaction at room temperature. The synthesis of structurally challenging pyrano[2,3‐c]carbazoles was achieved by using Pd(OAc)2 as a catalyst, K2CO3 as a base, and oxygen (O2) as a terminal oxidant through an intramolecular oxidative C−N bond‐forming reaction.
Zinc‐Mediated syn‐Selective Crotylation of N‐Unsubstituted Imines
Authors: Lee Won Jong , Jeong Wook , Park Jaiwook , Rhee Young Ho 
Published: January 2017

AbstractThe first example of a zinc‐mediated diastereoselective crotylation of N‐unsubstititued imines is described. The use of Et3B as an additive was of crucial importance to achieve high yield and diastereoselectivity. Notably, a high level of syn‐selectivity was observed. A mechanism involving an open transition state is suggested to explain this unique selectivity.
Effects of Lewis Acids on Photoredox Catalysis
Authors: Fukuzumi Shunichi , Jung Jieun , Lee Yong‐Min , Nam Wonwoo 
Published: January 2017

AbstractThe reactivity of organic photoredox catalysts in oxidation reactions is enhanced by the addition of Lewis acids, which bind to the catalyst to increase its oxidizing ability. Redox‐inactive metal ions, such as Sc3+, also act as Lewis acids and can bind to flavins to increase their one‐electron reduction potentials and photocatalytic stability. The Sc3+ ion can bind to acridine and pyrene to enhance their photoredox catalytic activity in the oxidation of substrates by dioxygen. The binding of Lewis acids to radical anions enhances their overall photocatalytic activity by prohibiting a back electron transfer from the radical anions of substrates to the oxidized photocatalysts. The photocatalytic asymmetric oxidation of terminal olefins by using water as the oxygen source with a mononuclear nonheme chiral manganese complex has been made possible by the addition of acetic acid, which is essential to afford the products with high enantioselectivity.
“Inherently Chiral” Ionic‐Liquid Media: Effective Chiral Electroanalysis on Achiral Electrodes
Authors: Rizzo Simona , Arnaboldi Serena , Mihali Voichita , Cirilli Roberto , Forni Alessandra , Gennaro Armando , Isse Abdirisak Ahmed , Pierini Marco , Mussini Patrizia Romana , Sannicolò Francesco 
Published: January 2017

AbstractTo achieve enantioselective electroanalysis either chiral electrodes or chiral media are needed. High enantiodiscrimination properties can be granted by the “inherent chirality” strategy of developing molecular materials in which the stereogenic element responsible for chirality coincides with the molecular portion responsible for their specific properties, an approach recently yielding outstanding performances as electrode surfaces. Inherently chiral ionic liquids (ICILs) have now been prepared starting from atropisomeric 3,3′‐bicollidine, synthesized from inexpensive reagents, resolved into antipodes without need of chiral HPLC and converted into long‐chain dialkyl salts with melting points below room temperature. Both the new ICILs and shorter family terms, solid at room temperature, employed as low‐concentration additives in achiral ILs, afford impressive enantioselection for the enantiomers of different probes on achiral electrodes, regularly increasing with additive concentration.
Asymmetrische Redoxarylierung: Chiralitätstransfer von Schwefel zu Kohlenstoff durch sigmatrope Sulfonium‐[3,3]‐Umlagerung
Authors: Kaldre Dainis , Maryasin Boris , Kaiser Daniel , Gajsek Oliver , González Leticia , Maulide Nuno 
Published: January 2017

AbstractEine allgemeine asymmetrische Redoxarylierung von Inamiden und Thioalkinen mit chiralen Sulfoxiden wird vorgestellt. Es handelt sich um das erste Beispiel eines allgemeinen 1,4‐Chiralitätstransfers von Schwefel zu Kohlenstoff durch [3,3]‐sigmatrope Umlagerung eines Sulfoniumintermediats. Die Reaktion liefert α‐arylierte Thioester und Amide in atomökonomischer Weise und unter milden Bedingungen. Die Produkte werden in hohen Ausbeuten und mit bis zu 99.5:0.5 Enantiomerenverhältnis erhalten. Quantenchemische Rechnungen legen für den Chiralitätstransfer einen Mechanismus nahe, der mit den experimentell beobachteten Korrelationen zwischen Enantioselektivität und Katalysator/Substrat übereinstimmt.
Highly Stereoselective Gold‐Catalyzed Coupling of Diazo Reagents and Fluorinated Enol Silyl Ethers to Tetrasubstituted Alkenes
Authors: Liao Fu‐Min , Cao Zhong‐Yan , Yu Jin‐Sheng , Zhou Jian 
Published: January 2017

AbstractWe report a highly stereoselective synthesis of all‐carbon or fluorinated tetrasubstituted alkenes from diazo reagents and fluorinated enol silyl ethers, using C−F bond as a synthetic handle. Cationic AuI catalysis plays a key role in this reaction. Remarkable fluorine effects on the reactivity and selectivity was also observed.
A False‐Positive Screening Hit in Fragment‐Based Lead Discovery: Watch out for the Red Herring
Authors: Cramer Jonathan , Schiebel Johannes , Wulsdorf Tobias , Grohe Kristof , Najbauer Eszter Eva , Ehrmann Frederik R. , Radeva Nedyalka , Zitzer Nina , Linne Uwe , Linser Rasmus , Heine Andreas , Klebe Gerhard 
Published: January 2017

AbstractWith the rising popularity of fragment‐based approaches in drug development, more and more attention has to be devoted to the detection of false‐positive screening results. In particular, the small size and low affinity of fragments drives screening techniques to their limit. The pursuit of a false‐positive hit can cause significant loss of time and resources. Here, we present an instructive and intriguing investigation into the origin of misleading assay results for a fragment that emerged as the most potent binder for the aspartic protease endothiapepsin (EP) across multiple screening assays. This molecule shows its biological effect mainly after conversion into another entity through a reaction cascade that involves major rearrangements of its heterocyclic scaffold. The formed ligand binds EP through an induced‐fit mechanism involving remarkable electrostatic interactions. Structural information in the initial screening proved to be crucial for the identification of this false‐positive hit.
An Asymmetric Redox Arylation: Chirality Transfer from Sulfur to Carbon through a Sulfonium [3,3]‐Sigmatropic Rearrangement
Authors: Kaldre Dainis , Maryasin Boris , Kaiser Daniel , Gajsek Oliver , González Leticia , Maulide Nuno 
Published: January 2017

AbstractA general, asymmetric redox arylation of ynamides and thioalkynes with chiral sulfoxides is reported. This is the first example of a general 1,4‐chirality transfer from sulfur to a carbon stereocenter through a sulfonium [3,3]‐sigmatropic rearrangement. This reaction delivers α‐arylated thioesters and amides under mild conditions in an atom‐economical manner. The products are formed in high yields with enantiomeric ratios up to 99.5:0.5. Quantum chemical calculations suggest a mechanism for the chirality transfer from sulfur to carbon and explain the experimentally observed correlation of the enantioselectivity with both the catalyst and the substrate.
Robust Aqua Material: A Pressure‐Resistant Self‐Assembled Membrane for Water Purification
Authors: Cohen Erez , Weissman Haim , Shimoni Eyal , Kaplan‐Ashiri Ifat , Werle Kai , Wohlleben Wendel , Rybtchinski Boris 
Published: January 2017

Abstract“Aqua materials” that contain water as their major component and are as robust as conventional plastics are highly desirable. Yet, the ability of such systems to withstand harsh conditions, for example, high pressures typical of industrial applications has not been demonstrated. We show that a hydrogel‐like membrane self‐assembled from an aromatic amphiphile and colloidal Nafion is capable of purifying water from organic molecules, including pharmaceuticals, and heavy metals in a very wide range of concentrations. Remarkably, the membrane can sustain high pressures, retaining its function. The robustness and functionality of the water‐based self‐assembled array advances the idea that aqua materials can be very strong and suitable for demanding industrial applications.
The ‘Paradox of Diversity’: Economic Evidence from US Cities 1980–2010
Authors: Ratna Nazmun , Grafton R. Quentin , To Hang 
Published: January 2017

AbstractWe evaluate the economic significance of linguistic barriers to communication in 226 US cities from 1980 to 2010. We address the question: to what extent do linguistic barriers across social groups inhibit the benefits of knowledge exchange? The empirical results show that linguistic, racial and composite diversity increase the average income of working age population in American cities. This positive effect of diversity, however, diminishes the higher is the proportion of foreign‐born population who lack English fluency. We call this the ‘paradox of diversity’. Overall, our findings provide important policy insights about how social diversity may enhance economic performance within cities.
Child Protection and Maltreatment in the Philippines: A Systematic Review of the Literature
Authors: Roche Steven 
Published: January 2017

AbstractTo gain a better understanding of the dimensions, characteristics and phenomenon of child maltreatment and its policy responses in the Philippines, this article provides a systematic review of the peer reviewed literature. This review provides a summary and analysis of the core child maltreatment issues in the Philippines and examines child protection policy responses. It takes a systematic approach, identifying 31 peer reviewed articles from a diverse range of scholarship that met its criteria, and subjected to a quality appraisal tool. Its findings provide important details about child maltreatment and child protection arrangements in the Philippines. It recommends further research into policy and programmatic approaches to child maltreatment, a greater focus on the social, cultural and structural influences on child maltreatment, and investigation into child maltreatment, particularly child sexual abuse, in contexts outside of the home, such as in institutions.
Seasonal encounter rate, life stages and main threats to the loggerhead sea turtle (Caretta caretta) in the Aeolian Archipelago (southern Thyrrenian Sea)
Authors: Blasi Monica Francesca , Mattei Daniela 
Published: January 2017

Abstract

Annual and seasonal encounter rates, life stages and the main threats to loggerhead sea turtles (Caretta caretta) in the Aeolian Archipelago (southern Italy) were studied.
Dedicated boat surveys resulted in 258 surface observations and 138 captures of healthy (n = 309), ailing (n = 66) and dead (n = 21) turtles from 2009 to 2013.
Loggerheads were encountered at the sea water surface while resting (87%) or feeding on pelagic prey (13%).
The loggerhead encounter rate (observations per km surveyed) was higher during the autumn, suggesting the presence of potential foraging/overwintering habitats in the area.
The mean (± SD) curved carapace length (CCL) was 48.8 ± 10.7 cm, with 65% of the individuals ranging from 40–70 cm in size. Smaller turtles were encountered more frequently during the spring months, probably as a result of the abundant pelagic prey within the coastal area. During the colder season, larger turtles were more common in the afternoon than in the morning, suggesting that the time needed for rewarming might increase with turtle size.
Ingestion of anthropogenic debris was reported in 48.5% of the rescued turtles. Individual mortality was mainly related to longline fishing (70.6%), with debris entanglements/ingestion frequently associated with these records. Longline bycatch and boat collisions were higher in summer, whereas debris ingestion was highest in spring. Different threats might affect particular life stages because the longline bycatch was more frequent for larger turtles, whereas boat collisions were more frequent with smaller individuals.
Migratory patterns, habitat characteristics and seasonal changes in sea temperature and currents might influence the seasonal occurrence of loggerhead turtles in this area.
These results increase the current ecological knowledge of the factors driving loggerhead turtle life and are important for implementing management plans for its conservation in the Mediterranean Sea.
Supramolecular Helical Nanofibers Formed by Achiral Monomers and Their Reversible Sol–Gel Transition
Authors: Wang Wen‐Zhi , Gao Chuan , Zhang Qi , Ye Xu‐Hao , Qu Da‐Hui 
Published: January 2017

AbstractWell‐defined supramolecular helical nanofibers have been constructed by a rationally designed achiral monomer in aqueous solution based on the 1:2 host–guest combination between cucurbit[8]uril and a 4,4′‐bipyridin‐1‐ium chloride (BPY+) salt derivative. The formed nanostructures could be adjusted by varying the concentration of monomer from helical nanofibers to a pH‐responsive hydrogel.
The self‐sufficient P450 RhF expressed in a whole cell system selectively catalyses the 5‐hydroxylation of diclofenac
Authors: Klenk Jan M. , Nebel Bernd A. , Porter Joanne L. , Kulig Justyna K. , Hussain Shaneela A. , Richter Sven M. , Tavanti Michele , Turner Nicholas J. , Hayes Martin A. , Hauer Bernhard , Flitsch Sabine L. 
Published: January 2017

AbstractP450 monooxygenases are able to catalyze the highly regio‐ and stereoselective oxidations of many organic molecules. However, the scale‐up of such bio‐oxidations remains challenging due to the often‐low activity, level of expression and stability of P450 biocatalysts. Despite these challenges they are increasingly desirable as recombinant biocatalysts, particularly for the production of drug metabolites. Diclofenac is a widely used anti‐inflammatory drug that is persistent in the environment along with the 4'‐ and 5‐hydroxy metabolites. Here we have used the self‐sufficient P450 RhF (CYP116B2) from Rhodococcus sp. in a whole cell system to reproducibly catalyze the highly regioselective oxidation of diclofenac to 5‐hydroxydiclofenac. The product is a human metabolite and as such is an important standard for environmental and toxicological analysis. Furthermore, access to significant quantities of 5‐hydroxydiclofenac has allowed us to demonstrate further oxidative degradation to the toxic quinoneimine product. Our studies demonstrate the potential for gram‐scale production of human drug metabolites through recombinant whole cell biocatalysis.
MDM tool: A data mining framework integrated into Moodle
Authors: Luna J. M. , Castro C. , Romero C. 
Published: January 2017

ABSTRACTThe interest in developing Learning Analytics tools that can be integrated into the well‐known Moodle course management systems is increasing nowadays. These tools generally provide some type of basic analytics and graphs about users' interaction in the course. However, they do not enable a varied set of Data Mining techniques to be applied, such as approaches for classification, clustering, or association. To address this issue, a new and freely available Moodle Data Mining tool, named MDM, has been proposed in this paper. The proposed tool eases the whole knowledge discovery process, including tasks such as selection, data pre‐processing, and data mining from Moodle courses. The proposed MDM tool has been developed in PHP programming language, so it can be easily integrated into Moodle as a module for a specific course. Its main features and architecture are described in depth, and a tutorial is also provided as a practical way of using the MDM interface. Finally, some experimental results using a real‐life sample dataset of mechanical engineering students are analyzed. © 2017 Wiley Periodicals, Inc. Comput Appl Eng Educ 25:90–102, 2017; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21782
Analysis of water distribution networks using MATLAB and Excel spreadsheet: h‐based methods
Authors: Niazkar Majid , Afzali Seied Hosein 
Published: January 2017

ABSTRACTThe need for computer application for solving water distribution networks (WDNs) is inevitable for both educational and practical purposes. In this paper, three h‐based methods for solving WDN including h‐based Newton–Raphson method, finite element method, and gradient algorithm are implemented using MATLAB and Excel spreadsheet. The input data should be first inserted into Excel spreadsheet while MATLAB codes utilize this data to solve the pipe network. The output results are also presented in Excel for convenience. As educational facets of this application was the main focus of this paper, the details of this computer application were step‐by‐step explained with codes. Furthermore, a simple network selected from literature was analyzed using the three h‐based methods. Finally, the presented codes and this computer application are believed to encourage many educators and applicants to assess them for both educational and practical purposes in this engineering field. © 2017 Wiley Periodicals, Inc. Comput Appl Eng Educ 25:129–141, 2017; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21786
A Multi‐Mitochondrial Anticancer Agent that Selectively Kills Cancer Cells and Overcomes Drug Resistance
Authors: Peng Yong Bo , Zhao Zi Long , Liu Teng , Xie Guo Jian , Jin Cheng , Deng Tang Gang , Sun Yang , Li Xiong , Hu Xiao Xiao , Zhang Xiao Bing , Ye Mao , Tan Wei Hong 
Published: January 2017

AbstractMitochondria are double‐membrane‐bound organelles involved mainly in supplying cellular energy, but also play roles in signaling, cell differentiation, and cell death. Mitochondria are implicated in carcinogenesis, and therefore dozens of lethal signal transduction pathways converge on these organelles. Accordingly, mitochondria provide an alternative target for cancer management. In this study, F16, a drug that targets mitochondria, and chlorambucil (CBL), which is indicated for the treatment of selected human neoplastic diseases, were covalently linked, resulting in the synthesis of a multi‐mitochondrial anticancer agent, FCBL. FCBL can associate with human serum albumin (HSA) to form an HSA–FCBL nanodrug, which selectively recognizes cancer cells, but not normal cells. Systematic investigations show that FCBL partially accumulates in cancer cell mitochondria to depolarize mitochondrial membrane potential (MMP), increase reactive oxygen species (ROS), and attack mitochondrial DNA (mtDNA). With this synergistic effect on multiple mitochondrial components, the nanodrug can effectively kill cancer cells and overcome multiple drug resistance. Furthermore, based on its therapeutic window, HSA–FCBL exhibits clinically significant differential cytotoxicity between normal and malignant cells. Finally, while drug dosage and drug resistance typically limit first‐line mono‐chemotherapy, HSA–FCBL, with its ability to compromise mitochondrial membrane integrity and damage mtDNA, is expected to overcome those limitations to become an ideal candidate for the treatment of neoplastic disease.
Hexagonal Boron Nitride (h‐BN) Sheets Decorated with OLi, ONa, and Li2F Molecules for Enhanced Energy Storage
Authors: Naqvi Syeda Rabab , Rao Gollu Sankar , Luo Wei , Ahuja Rajeev , Hussain Tanveer 
Published: January 2017

AbstractFirst‐principles electronic structure calculations were carried out on hexagonal boron nitride (h‐BN) sheets functionalized with small molecules, such as OLi, ONa, and Li2F, to study their hydrogen (H2) storage properties. We found that OLi and ONa strongly adsorb on h‐BN sheets with reasonably large inter‐adsorbent separations, which is desirable for H2storage. Ab initio molecular dynamics (MD) simulations further confirmed the structural stability of OLi‐BN and ONa‐BN systems at 400 K. On the other hand, Li2F molecules form clusters over the surface of h‐BN at higher temperatures. We performed a Bader charge investigation to explore the nature of binding between the functionalized molecules and h‐BN sheets. The density of states (DOS) revealed that functionalized h‐BN sheets become metallic with two‐sided coverage of each type of molecules. Hydrogenation of OLi‐BN and ONa‐BN revealed that the functionalized systems adsorb multiple H2molecules around the Li and Na atoms, with H2adsorption energies ranging from 0.20 to 0.28 eV, which is desirable for an efficient H2storage material.
AmphiBase: A new genomic resource for non‐model amphibian species
Authors: Kwon Taejoon 
Published: January 2017

AbstractMore than five thousand genes annotated in the recently published Xenopus laevis and Xenopus tropicalis genomes do not have a candidate orthologous counterpart in other vertebrate species. To determine whether these sequences represent genuine amphibian‐specific genes or annotation errors, it is necessary to analyze them alongside sequences from other amphibian species. However, due to large genome sizes and an abundance of repeat sequences, there are limited numbers of gene sequences available from amphibian species other than Xenopus. AmphiBase is a new genomic resource covering non‐model amphibian species, based on public domain transcriptome data and computational methods developed during the X. laevis genome project. Here, I review the current status of AmphiBase, including amphibian species with available transcriptome data or biological samples, and describe the challenges of building a comprehensive amphibian genomic resource in the absence of genomes. This mini‐review will be informative for researchers interested in functional genomic experiments using amphibian model organisms, such as Xenopus and axolotl, and will assist in interpretation of results implicating “orphan genes.” Additionally, this study highlights an opportunity for researchers working on non‐model amphibian species to collaborate in their future efforts and develop amphibian genomic resources as a community.