bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Overview of the Species and Ecological Diversity of Ants
Authors: Guénard Benoit 
Published: May 2013

AbstractSince their appearance during the Cretaceous, ants have diversified to become today the most diverse group of social insects and one of the most influential groups of organisms on the planet. More than 12 500 species of ants are presently described, distributed within 21 subfamilies, with a large majority of the species belonging to only four subfamilies. Ants are present in almost all terrestrial ecosystems, their peak of diversity is found within the tropical regions, and ant richness tends to decline both with increasing latitude and altitude. In most ecosystems the ecological importance of ants, involved in numerous interactions with organisms ranging from bacteria, plants, fungi, arthropods to vertebrates, plays a critical role in the survival or control of many species. Finally, despite the tremendous efforts to understand ant biology over the past decades, the ecology of most species is still poorly understood and many new species are expected to be discovered.Key Concepts:Ants, Formicidae, appeared during the Cretaceous period.Modern ants arise during the Eocene period and then became an important part of insect communities.More than 12 500 species of ants are known today, with many species still unknown, and most of the current species belong to four subfamilies: the Myrmicinae, Formicinae, Ponerinae and Dolichoderinae.Like many other organisms, ants present a latitudinal gradient of species richness, with the highest richness found within the tropical regions.Ant species richness tends to decrease with elevation, and become extremely scarce for an elevation above 2500 m, but can be present up to 4800 m.Through herbivory, predation or mutualistic interactions, ants contribute to the regulation and survival of many organisms.The modifications of the abiotic conditions within and around the nest ants occupy create favourable habitats for many organisms and as such ants can be perceived as ecosystem engineers.Much work, especially in taxonomy, ecology and biogeography of ants is still needed to fully address questions related to large‐scale patterns and processes by which ants became and are still successful.
Identifying New Targets for Personalised Cancer Therapy
Authors: Link W , Madureira PA , Hill R 
Published: May 2013

AbstractPersonalised medicine requires the use of patient‐specific information to predict individual responses to disease treatment. Consequently, this approach requires the diagnostic ability to stratify patients based on their potential to benefit from a specific treatment (as opposed to an alternative) and the availability of molecularly targeted therapies. On the basis of the heterogeneity of the disease, cancer diagnosis and therapy is currently at the forefront of personalised medicine. Cancer therapy is currently undergoing a significant paradigm change, from nonspecific cytotoxic agents to considerably more specific approaches based on the unique molecular features of cancer cells. The identification and validation of disease relevant targets is crucial for the development of molecularly targeted anticancer therapies. Our advancing understanding of the molecular basis of cancer in tandem with novel approaches to interfere with signal transduction pathways have opened new horizons for anticancer target discovery. Specifically, the image‐based large‐scale analysis of cellular phenotypes that arise from genetic or chemical perturbations paved the way for the identification and validation of disease relevant molecular targets independent of preconceived notions of mechanistic relationships.Key Concepts:Cancer therapy is undergoing a change from nonspecific cytotoxic to molecularly targeted treatment.Targeted cancer therapies need new relevant targets.A good therapeutic target is essential and specific.Targeting specific molecular targets are expected to be beneficial only for a subset of patients.Companion diagnostics based on specific biomarkers is essential to guide treatment decisions.Targeted treatment has to be intimately linked to the causal changes for each neoplasm.The selection of appropriate combinations of molecular targets specific for different cancers will be essential to develop successful anticancer therapies.Image‐based high content screening allows for the identification of disease relevant molecular targets independent of preconceived notions of mechanistic relationships.
Platinum on Carbon‐Catalyzed H–D Exchange Reaction of Aromatic Nuclei due to Isopropyl Alcohol‐Mediated Self‐ Activation of Platinum Metal in Deuterium Oxide
Authors: Sawama Yoshinari , Yamada Tsuyoshi , Yabe Yuki , Morita Kosuke , Shibata Kyoshiro , Shigetsura Masahiro , Monguchi Yasunari , Sajiki Hironao 
Published: May 2013

AbstractAn efficient and simple deuteration method of arenes using the platinum on carbon‐isopropyl alcohol‐cyclohexane‐deuterium oxide combination under hydrogen gas‐free conditions was accomplished. Since the hydrogen–deuterium exchange reaction cannot be promoted without isopropyl alcohol, zerovalent platinum metal (on carbon) is self‐activated by the in situ‐generated very low amount of hydrogen or hydrogen–deuterium gas derived from isopropyl alcohol or isopropyl alcohol‐d1. Deuterium‐labeled compounds with high deuterium contents can be easily isolated by the filtration of platinum on carbon and simple extraction. The present hydrogen gas‐free method is safe from the viewpoint of process chemistry and various arenes possessing a variety of reducible functionalities within the molecule could be effectively and directly deuterium‐labeled without undesired reduction.
Superbase‐Catalyzed [4+2] Cycloaddition of Acetylenes to 3,6‐Di(pyrrol‐2‐yl)‐1,2,4,5‐tetrazine: A Facile Synthesis of 3,6‐Di(pyrrol‐2‐yl)pyridazines
Authors: Trofimov Boris A. , Glotova Tatyana E. , Shabalin Dmitrii A. , Dvorko Marina Yu. , Ushakov Igor A. , Schmidt Elena Yu. , Kuzmin Anton V. , Mikhaleva Al'bina I. 
Published: May 2013

AbstractAcetylenes undergo the [4+2] cycloaddition to 3,6‐di(pyrrol‐2‐yl)‐1,2,4,5‐tetrazine in the potassium hydroxide/dimethyl sulfoxide or potassium tert‐butoxide/dimethyl sulfoxide systems (80 °C, 2.5–4 h) to afford (after extrusion of the nitrogen molecule from the intermediate) 3,6‐di(pyrrol‐2‐yl)pyridazines in up to 73% yield, while under non‐catalytic conditions this reaction does not take place. This unusual result substantially extends the scope of synthetic application and mechanistic diversity of the Diels–Alder reaction. The step‐wise mechanisms involving the formation of [OH/tetrazine]− or [t‐BuO/tetrazine]− anionic intermediate complexes or cycloaddition of tetrazine to the acetylide anion are considered.
Efficient and Green Route to γ‐Lactams by Copper‐Catalysed Reversed Atom Transfer Radical Cyclisation of α‐Polychloro‐N‐allylamides, using a Low Load of Metal (0.5 mol%)
Authors: Bellesia Franco , Clark Andrew J. , Felluga Fulvia , Gennaro Armando , Isse Abdirisak A. , Roncaglia Fabrizio , Ghelfi Franco 
Published: May 2013

AbstractThe cyclisation of N‐allyl‐N‐substituted‐α‐polychloroamides is efficiently obtained through a copper‐catalysed activators regenerated by electron transfer–atom transfer radical cyclisation process, with a metal load of only 0.5 mol%. The redox catalyst is introduced in its inactive form as copper(II) chloride/[nitrogen ligand] complex, and continuously regenerated to the active copper(I) chloride/[nitrogen ligand] species by ascorbic acid. To preserve the catalyst integrity, the hydrochloric acid, released after each regeneration cycle, has been quenched by carbonate. The choice of the solvent is critical, the best performance being observed in ethyl acetate‐ethanol (3:1).
Catalytic Asymmetric Hydrogenation of α‐Arylcyclohexanones and Total Synthesis of (−)‐α‐Lycorane
Authors: Li Gang , Xie Jian‐Hua , Hou Jing , Zhu Shou‐Fei , Zhou Qi‐Lin 
Published: May 2013

AbstractAn efficient catalytic asymmetric hydrogenation of racemic α‐arylcyclohexanones with an ethylene ketal group at the 5‐position of the cyclohexane ring via dynamic kinetic resolution has been developed, giving chiral α‐arylcyclohexanols with two contiguous stereocenters with up to 99% ee and >99:1 cis/trans‐selectivity. Using this highly efficient asymmetric hydrogenation reaction as a key step, (−)‐α‐lycorane was synthesized in 19.6% overall yield over 13 steps from commercially available starting material.
Visible Light‐Induced Aerobic Oxyamidation of Indoles: A Photocatalytic Strategy for the Preparation of Tetrahydro‐5H‐indolo[2,3‐b]quinolinols
Authors: An Jing , Zou You‐Quan , Yang Qing‐Qing , Wang Qiang , Xiao Wen‐Jing 
Published: May 2013

AbstractA visible light‐induced, aerobic oxyamidation reaction of indoles, using air as the sole oxidant, has been developed. This process serves as a photocatalytic strategy to generate efficiently tetrahydro‐5H‐indolo[2,3‐b]quinolinols, which may have interesting biological and pharmacological activities owing to their privileged indoline structure.
Palladium‐Catalyzed Regioselective and Stereoselective Oxidative Heck Arylation of Allylamines with Arylboronic Acids
Authors: Zhang Lingjuan , Dong Chaonan , Ding Chenjun , Chen Jing , Tang Weijun , Li Huanrong , Xu Lijin , Xiao Jianliang 
Published: May 2013

AbstractA general and convenient palladium‐catalyzed oxidative Heck arylation of both N‐protected and N,N‐diprotected allylic amines with arylboronic acids under mild conditions has been developed. The catalyst system, consisting of Pd(OAc)2 (palladium acetate), AgOAc (silver acetate) and KHF2 (potassium hydrogen fluoride), could efficiently catalyze the coupling reaction in acetone without the aid of any ligand, leading exclusively to the γ‐arylated allylic amine products in good to excellent yields. This method is highlighted with excellent regio‐ and stereocontrol and remarkable functional group tolerance. The carbamate moiety in allylic amine substrates is of crucial importance to the catalytic performance, and the chelation between the carbonyl O (oxygen) and Pd (palladium) atoms is believed to be responsible for the high regioselectivity and stereoselectivity observed.
Ethynylbenziodoxolones (EBX) as Reagents for the Ethynylation of Stabilized Enolates
Authors: Fernández González Davinia , Brand Jonathan P. , Mondière Régis , Waser Jérôme 
Published: May 2013

AbstractHerein, we report a detailed study on the electrophilic alkynylation of cyclic keto esters and amides with ethynylbenziodoxolone (EBX) reagents. The structure and stability of this class of reagents is first described more in details. Differential scanning calorimetry (DSC) experiments showed a strong exothermic decomposition with EBX reagents, leading to guidelines for the safe use of these compounds. The extension of the method to aromatic alkynes and a broad range of benziodoxol(on)e reagents is then reported. Based on our preliminary results using Cinchona‐based phase‐transfer catalysts, the enantioselective alkynylation of cyclic keto esters could be achieved. Binaphthyl‐derived ammonium catalysts developed by Maruoka and co‐workers gave the highest asymmetric induction with up to 79% ee for an indanone‐derived keto ester. Throughout this work, asymmetric induction was observed only in the case of benziodoxolone reagents, demonstrating their superiority over conventional alkynyliodonium salts. The deeper understanding gained about the factors leading to higher asymmetric induction will be very useful in the future to develop a truly general and highly enantioselective alkynylation method.
Testing for post‐copulatory selection for major histocompatibility complex genotype in a semi‐free‐ranging primate population
Authors: Setchell Joanna M. , Abbott Kristin M. , Gonzalez Jean‐Paul , Knapp Leslie A. 
Published: May 2013

AbstractA large body of evidence suggests that major histocompatibility complex (MHC) genotype influences mate choice. However, few studies have investigated MHC‐mediated post‐copulatory mate choice under natural, or even semi‐natural, conditions. We set out to explore this question in a large semi‐free‐ranging population of mandrills (Mandrillus sphinx) using MHC‐DRB genotypes for 127 parent–offspring triads. First, we showed that offspring MHC heterozygosity correlates positively with parental MHC dissimilarity suggesting that mating among MHC dissimilar mates is efficient in increasing offspring MHC diversity. Second, we compared the haplotypes of the parental dyad with those of the offspring to test whether post‐copulatory sexual selection favored offspring with two different MHC haplotypes, more diverse gamete combinations, or greater within‐haplotype diversity. Limited statistical power meant that we could only detect medium or large effect sizes. Nevertheless, we found no evidence for selection for heterozygous offspring when parents share a haplotype (large effect size), genetic dissimilarity between parental haplotypes (we could detect an odds ratio of ≥1.86), or within‐haplotype diversity (medium‐large effect). These findings suggest that comparing parental and offspring haplotypes may be a useful approach to test for post‐copulatory selection when matings cannot be observed, as is the case in many study systems. However, it will be extremely difficult to determine conclusively whether post‐copulatory selection mechanisms for MHC genotype exist, particularly if the effect sizes are small, due to the difficulty in obtaining a sufficiently large sample. Am. J. Primatol. 75:1021–1031, 2013. © 2013 Wiley Periodicals, Inc.
Kinetics of the dissolution of ilmenite in oxalic and sulfuric acid solutions
Authors: Jonglertjunya Woranart , Rattanaphan Santita , Tipsak Pitchayawadee 
Published: May 2013

ABSTRACTIn this study, the effects of particle size, type and concentration of acid solution on dissolution kinetics of ilmenite are investigated. The results showed that both oxalic and sulfuric acid and their concentrations had relatively high effects on the dissolution rate of titanium, which increased with an increase in acid concentration. About 86.4% of titanium could be leached in 10 h when using 4 M oxalic acid, 1 : 20 solid/liquid ratio, 90 °C temperature and particle size less than 45 µm. Under similar experimental conditions with the exception of sulfuric acid concentrations of 4, 8 and 12 M, the titanium solubilization was 16.1%, 48.2% and 52.0%, respectively. The experimental data followed reaction kinetics and indicated that the shrinking particle model controlled the chemical reaction. The observed titanium dissolution rates could be expressed as 1 − (1 − x)1/3 = 0.0092C1.2022t for oxalic acid for concentration varying between 1 and 4 M and 1 − (1 − x)1/3 = 0.0006C1.5977t for sulfuric acid for concentration varying between 2 and 12 M, respectively. The fitted models for estimating the titanium dissolution rate from the experimental data indicated good accuracy with coefficient of determination (R2) higher than 0.96. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.
ALOS PALSAR Analysis of the Archaeological Site of Pelusium
Authors: Stewart Christopher , Lasaponara Rosa , Schiavon Giovanni 
Published: May 2013

ABSTRACTAn analysis of the archaeological site of Pelusium on the northeastern edge of the Nile Delta, Egypt, was carried out using phased array type L‐band synthetic aperture radar (PALSAR) data. The aim was to assess the potential of PALSAR to identify buried archaeological structures. The 18 PALSAR images acquired in various polarimetric modes were obtained for the analysis through a European Space Agency Category‐1 project. Processing included co‐registration and summation of images for each polarimetric mode in order to reduce speckle. The summed images were then compared with each other and with optical imagery to identify any features that may be of archaeological interest. Features identified on the summed images were also viewed in the individual images to assess their ephemeral nature. One image was available in quadrupole polarization (quad‐pol) mode with which polarimetric analysis was undertaken, including extraction of target decompositions and analysis of the scattering characteristics of the study area. Linear and geometric features that may be archaeological structures were visible in the processed SAR imagery. Possible palaeolandscape features were also identified. Some of these are visible in the optical imagery, but not clearly delineated. The results of the polarimetric analysis show that single‐bounce scattering dominates over the study area, and that over the sandy regions the signal is much weaker in all polarizations, with mixed scattering. Although the spatial resolution did not enable clear identification and characterization of the physical scattering properties of small‐scale features, the PALSAR data demonstrate a capability to highlight features that become almost invisible in optical imagery at the synoptic scale (even if they are visible up close) leading to the conclusion that PALSAR may be a useful tool in the first stages of archaeological surveys to analyse the spatial pattern of features, and identify where to focus smaller scale surveys in areas with land cover similar to that of the study area. Copyright © 2013 John Wiley & Sons, Ltd.
One‐Pot, Template‐Free Synthesis of PdPt Single‐Crystalline Hollow Cubes with Enhanced Catalytic Activity
Authors: Sun Long , Zhang Zhicheng , Xu Biao , Wang Xun 
Published: May 2013

AbstractHollow structures have attracted ever‐growing interest owing to their various excellent properties. However, a facile strategy for their fabrication is still desired. Herein, PdPt alloy with three different morphologies, that is, cubes, hollow cubes, and truncated octahedrons, is synthesized by using a one‐pot, template‐free method. The mechanism and dynamics of this system is also studied in detail. In particular, the hollow cubic structure represents enhanced catalytic activity in both coupling reactions and in the electrochemical oxidation of formic acid.
Probing the Coordination Environment of the Human Copper Chaperone HAH1: Characterization of HgII‐Bridged Homodimeric Species in Solution
Authors: Łuczkowski Marek , Zeider Brian A. , Hinz Alia V. H. , Stachura Monika , Chakraborty Saumen , Hemmingsen Lars , Huffman David L. , Pecoraro Vincent L. 
Published: May 2013

AbstractAlthough metal ion homeostasis in cells is often mediated through metallochaperones, there are opportunities for toxic metals to be sequestered through the existing transport apparatus. Proper trafficking of CuI in human cells is partially achieved through complexation by HAH1, the human metallochaperone responsible for copper delivery to the Wilson and Menkes ATPase located in the trans‐Golgi apparatus. In addition to binding copper, HAH1 strongly complexes HgII, with the X‐ray structure of this complex previously described. It is important to clarify the solution behavior of these systems and, therefore, the binding of HgII to HAH1 was probed over the pH range 7.5 to 9.4 using 199Hg NMR, 199mHg PAC and UV–visible spectroscopies. The metal‐dependent protein association over this pH range was examined using analytical gel‐filtration. It can be concluded that at pH 7.5, HgII is bound to a monomeric HAH1 as a two coordinate, linear complex (HgS2), like the HgII–Atx1 X‐ray structure (PDB ID: 1CC8). At pH 9.4, HgII promotes HAH1 association, leading to formation of HgS3 and HgS4 complexes, which are in exchange on the μs–ns time scale. Thus, structures that may represent central intermediates in the process of metal ion transfer, as well as their exchange kinetics have been characterized.
Changes in the Structural Dimensionality of Selenidostannates in Ionic Liquids: Formation, Structures, Stability, and Photoconductivity
Authors: Lin Yumei , Xie Dewang , Massa Werner , Mayrhofer Leonhard , Lippert Sina , Ewers Benjamin , Chernikov Alexey , Koch Martin , Dehnen Stefanie 
Published: May 2013

AbstractIn situ transformations of selenidostannate frameworks in ionic liquids (ILs) were initiated by treatment of the starting phase K2[Sn2Se5] and the consecutive reaction products by means of temperature increase and/or amine addition. Along the reaction pathway, the framework dimensionalities of the five involved selenidostannate anions develop from 3D to 1D and back, both in top‐down and bottom‐up style. Addition of ethane‐1,2‐diamine (en) led to the reversion of the 2D→1D step from 2D‐{[Sn24Se56]16−} to 1D‐{[Sn6Se14]4−}. As rationalized by DFT investigations, the 2D anion is thermodynamically favored. Photoconductivity measurements reveal that all samples show Schottky contact behavior with absolute thresholds below 10 V. One of the samples exhibits conductive states within the energy range of visible photons.
Investigation of Pharmacodynamic and Pharmacokinetic Interactions Between Rivaroxaban and Enoxaparin in Healthy Male Subjects
Authors: Kubitza Dagmar , Becka Michael , Schwers Stephan , Voith Barbara 
Published: May 2013

AbstractRivaroxaban, an oral, direct factor Xa inhibitor, is currently used in clinical practice for the prevention and treatment of thromboembolic disorders. This single‐center, three‐way crossover study was designed to investigate the pharmacodynamic effects of rivaroxaban (10 mg) and enoxaparin (40 mg) alone and in combination as well as the influence of enoxaparin on the pharmacokinetics of rivaroxaban in healthy male subjects. When given alone, both drugs exhibited similar, rapid anti‐factor Xa activity. Combined administration resulted in an increase of ∼50% in anti‐factor Xa activity and a lesser increase in activated partial thromboplastin time, compared with either drug alone. Enoxaparin had no additional effect on prolongation of the prothrombin time induced by rivaroxaban and did not affect the pharmacokinetic parameters of rivaroxaban. The results showed that rivaroxaban (10 mg) and enoxaparin (40 mg) had a similar and rapid onset of action, as indicated by the similar anti‐factor Xa activity–time curves, suggesting that both drugs have a similar duration of pharmacological activity at the factor X site. Co‐administration of rivaroxaban and enoxaparin is associated with enhanced pharmacodynamic effects.
Rational Design and Synthesis of Cyano‐Bridged Coordination Polymers with Precise­ Control of Particle Size from 20 to 500 nm
Authors: Chiang Ya‐Dong , Hu Ming , Kamachi Yuichiro , Ishihara Shinsuke , Takai Kimiko , Tsujimoto Yoshihiro , Ariga Katsuhiko , Wu Kevin C.‐W. , Yamauchi Yusuke 
Published: May 2013

AbstractWe demonstrate that the particle sizes in cyano‐bridged coordination polymers consisting of NiII–C≡N–FeII units are precisely controlled by changing the amount of chelating agent, sodium citrate. With an increase in the amount of chelating agent added, the average size of the particles gradually increases from 20 to 350 nm with retention of a well‐defined cubic shape. Furthermore, the use of different Fe sources expands the possible control range up to 500 nm.