bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microfluidic Synthesis of Rigid Nanovesicles for Hydrophilic Reagents Delivery
Authors: Zhang Lu , Feng Qiang , Wang Jiuling , Sun Jiashu , Shi Xinghua , Jiang Xingyu 
Published: February 2015

AbstractWe present a hollow‐structured rigid nanovesicle (RNV) fabricated by a multi‐stage microfluidic chip in one step, to effectively entrap various hydrophilic reagents inside, without complicated synthesis, extensive use of emulsifiers and stabilizers, and laborious purification procedures. The RNV contains a hollow water core, a rigid poly (lactic‐co‐glycolic acid) (PLGA) shell, and an outermost lipid layer. The formation mechanism of the RNV is investigated by dissipative particle dynamics (DPD) simulations. The entrapment efficiency of hydrophilic reagents such as calcein, rhodamine B and siRNA inside the hollow water core of RNV is ≈90 %. In comparison with the combination of free Dox and siRNA, RNV that co‐encapsulate siRNA and doxorubicin (Dox) reveals a significantly enhanced anti‐tumor effect for a multi‐drug resistant tumor model.
Deconstructing Covalent Organocatalysis
Authors: Holland Mareike C. , Gilmour Ryan 
Published: February 2015

AbstractModern organocatalysis has rapidly evolved into an essential component of contemporary organic synthesis. One of the most distinctive aspects of organocatalytic processes is the biomimetic nature in which the catalyst engages the substrate, often forming covalently bound intermediates in a manner reminiscent of enzyme catalysis. Indeed, the process of intramolecularization is often accompanied by a conformational change of the catalyst scaffold, further accentuating this analogy with biological systems. The isolation and study of these catalytic intermediates facilitate the rapid generation of conformation and reactivity profiles to assist in organocatalytic reaction development and/or clarify reaction outcomes. Emulating the formative advances that have derived from studying reaction intermediates in mechanistic organometallic and enzymatic catalysis, the deconstruction of covalently bound organocatalysis intermediates is gaining momentum as a design strategy.
Biomass‐Derived Carbon Quantum Dot Sensitizers for Solid‐State Nanostructured Solar Cells
Authors: Briscoe Joe , Marinovic Adam , Sevilla Marta , Dunn Steve , Titirici Magdalena 
Published: February 2015

AbstractNew hybrid materials consisting of ZnO nanorods sensitized with three different biomass‐derived carbon quantum dots (CQDs) were synthesized, characterized, and used for the first time to build solid‐state nanostructured solar cells. The performance of the devices was dependent on the functional groups found on the CQDs. The highest efficiency was obtained using a layer‐by‐layer coating of two different types of CQDs.
Encapsulation of Functional Organic Compounds in Nanoglass for Optically Anisotropic Coatings
Authors: Stöter Matthias , Biersack Bernhard , Rosenfeldt Sabine , Leitl Markus J. , Kalo Hussein , Schobert Rainer , Yersin Hartmut , Ozin Geoffrey A. , Förster Stephan , Breu Josef 
Published: February 2015

AbstractA novel approach is presented for the encapsulation of organic functional molecules between two sheets of 1 nm thin silicate layers, which like glass are transparent and chemically stable. An ordered heterostructure with organic interlayers strictly alternating with osmotically swelling sodium interlayers can be spontaneously delaminated into double stacks with the organic interlayers sandwiched between two silicate layers. The double stacks show high aspect ratios of >1000 (typical lateral extension 5000 nm, thickness 4.5 nm). This newly developed technique can be used to mask hydrophobic functional molecules and render them completely dispersible in water. The combination of the structural anisotropy of the silicate layers and a preferred orientation of molecules confined in the interlayer space allows polymer nanocomposite films to be cast with a well‐defined orientation of the encapsulated molecules, thus rendering the optical properties of the nanocoatings anisotropic.
Spatial genetic structure of dusky dolphin,Lagenorhynchus obscurus, along the argentine coast: preserve what scale?
Authors: Loizaga de Castro Rocio , Dans Silvana L. , Crespo Enrique A. 
Published: February 2015

AbstractThe dusky dolphin (Lagenorhynchus obscurus) represents one of the most abundant species of small cetacean in Argentine waters. During the 1980s and 1990s, high levels of incidental mortality in purse and trawl fisheries were documented, and in recent decades tourism activities have been added as a potential source of disturbance.The study objectives were to identify spatial genetic structure and regional genetic patterns of dusky dolphins along the Argentine coast. The variation of 413bp of the control region of 119 individuals over six locations spread along 2800 km (38°40'S to 54°30'S) was examined. Spatial genetic analyses, SAMOVA, genetic landscape shapes and autocorrelation analyses were conducted.The most probable configuration was K=2, island population vs. continental populations (FCT= 0.774) and the spatial autocorrelation analysis showed a strong regional genetic structure, defining an operational unit at < 50 km.The results provide valuable information that should be taken into account in the development of conservation strategies and management of the species; making the efforts focus on conserving vulnerable dusky dolphin groups by protecting their preferred coastal shallow habitat and by monitoring and regulating the dolphin watching and fishing activities, acting upon local populations along the Argentine coast.Copyright © 2015 John Wiley & Sons, Ltd.
Females Have Larger Ratio of Second‐to‐Fourth Digits Than Males in Four Species of Salamandridae, Caudata
Authors: Kaczmarski Mikołaj , Kubicka Anna Maria , Tryjanowski Piotr , Hromada Martin 
Published: February 2015

ABSTRACTDigit ratio (2D:4D) denotes the relative length of the second and fourth digits. It is considered to be a suitable biomarker of the in utero balance of fetal sex hormones, which affect early development of individuaĺs behavioral and morphological characteristics. In recent decades, digit ratio attracted a great attention in biology and psychology. However, for unmasking the biological basis of the phenomenon, extensive studies on non‐human animals are necessary. Despite it was hypothesized that digit ratio is well conserved in all Tetrapoda, and there exist studies on mammals, birds, and reptiles, there are only two such study on anuran amphibians. Therefore, the aim of this study is to investigate the 2D:4D in the most basal salamanders, Caudata. We have studied digit ratio in four species of newts: Triturus cristatus, Mesotriton alpestris, Lissotriton montandoni, and Lissotriton vulgaris, using museum collection. We used computerized measuring of each limbś photos. We have found out that, in M. alpestris, females 2D:4D of all four limbs were significantly larger than in males. In L. montandoni and L. vulgaris, only 2D:4D of rear limbs significantly differed, in females being larger. In T. cristatus, digit ratios of males and females did not statistically differ. Thus, the results confirmed our hypothesis that at least in M. alpestris, L. montandoni, and L. vulgaris, females seem to have larger 2D:4D comparing to males, the pattern known from most mammals and opposite to birds, reptiles and anuran amphibians. Anat Rec, 298:1424–1430, 2015. © 2015 Wiley Periodicals, Inc.
Pre‐Lapita decorated wood from Apalo, West New Britain, Papua New Guinea
Authors: Specht Jim , Lentfer Carol , Gosden Chris , Jacobsen Geraldine , Lindsay Sue 
Published: February 2015

AbstractIn 1989–1990, part of a wooden artefact with an incised criss‐cross design was recovered from the pre‐Lapita pottery level of the U‐L‐T area of the Apalo site in the Arawe Islands of New Britain, Papua New Guinea. The artefact was made from a Ficus tree species, and has been dated by AMS to 4043–3848 calBP (95.4%). This makes it the oldest directly dated ornamented object in the New Guinea region, though zoomorphic stone figurines and pestles and decorated stone mortars of the region are probably of similar antiquity. The artefact adds to the growing body of information about people in the Papua New Guinea Islands prior to the appearance of Lapita pottery, though the simplicity of the design and its widespread distribution in time and space caution against seeing it as a precursor to the Lapita design system. The nature of the original artefact is uncertain.
Designing New Analogs for Streamlining the Structure of Cytotoxic Lamellarin Natural Products
Authors: Tangdenpaisal Kassrin , Worayuthakarn Rattana , Karnkla Supatra , Ploypradith Poonsakdi , Intachote Pakamas , Sengsai Suchada , Saimanee Busakorn , Ruchirawat Somsak , Chittchang Montakarn 
Published: February 2015

AbstractDespite the therapeutic potential of marine‐derived lamellarin natural products, their preclinical development has been hampered by their lipophilic nature, causing very poor aqueous solubility. In order to develop more drug‐like analogs, their structure was streamlined in this study from both the cytotoxic activity and lipophilicity standpoints. First, a modified total synthetic route was successfully devised to construct a library of 59 systematically designed lamellarin analogs, which were then subjected to cytotoxicity and log P determinations. Along with the 25 first‐generation lamellarins previously synthesized in our laboratory, the structure–activity and structure–lipophilicity relationships were extensively evaluated. Our results clearly indicated the additional structural requirements around the lamellarin skeleton which, when combined with those reported previously, can provide invaluable guidance for further modifications to increase the aqueous solubility of these compounds.
An alternative laboratory designed to address ethical concerns associated with traditional TAS2R38 student genotyping
Authors: LaBonte Michelle L. , Beers Melissa A. 
Published: February 2015

AbstractThe TAS2R38 alleles that code for the PAV/AVI T2R38 proteins have long been viewed as benign taste receptor variants. However, recent studies have demonstrated an expanding and medically relevant role for TAS2R38. The AVI variant of T2R38 is associated with an increased risk of both colorectal cancer and Pseudomonas aeruginosa‐associated sinus infection and T2R38 variants have been implicated in off‐target drug responses. To address ethical concerns associated with continued student TAS2R38 gene testing, we developed an alternative to the traditional laboratory genotyping exercise. Instead of determining their own genotype, introductory level students isolated plasmid DNA containing a section of the human TAS2R38 gene from Escherichia coli. Following PCR‐mediated amplification of a section of the TAS2R38 gene spanning the SNP at position 785, students determined their assigned genotype by restriction enzyme digestion and agarose gel electrophoresis. Using the course wide genotype and phenotype data, students found that there was an association between TAS2R38 genotype and the age of persistent P. aeruginosa acquisition in cystic fibrosis “patients.” Assessment data demonstrated that students taking part in this new TAS2R38 laboratory activity made clear learning gains. © 2015 by The International Union of Biochemistry and Molecular Biology, 43(2):100–109, 2015.
Novel Approaches in Selective Tryptophan Isotope Labeling by Using Escherichia coli Overexpression Media
Authors: Schörghuber Julia , Sára Tomáš , Bisaccia Marilena , Schmid Walther , Konrat Robert , Lichtenecker Roman J. 
Published: February 2015

AbstractNMR‐based investigations of large protein complexes require optimized isotopic labeling schemes. We report new methods to introduce stable isotopes into tryptophan residues; these are fine‐tuned to the requirements of the particular protein NMR experiment. Selective backbone labeling was performed by using a new α‐ketoacid precursor as an additive in cell‐based overexpression media. Additionally, we developed synthetic routes to certain isotopologues of indole with 13C–1H spin systems surrounded by 12C and 2H. The corresponding proteins, overexpressed in the presence of these precursor compounds, can be effectively analyzed for conformational changes in tryptophan residues in response to external stimuli, such as interaction with other proteins or small molecules.
Unusual Bonding and Properties in Main Group Element Chemistry: Rational Synthesis, Characterization, and Experimental Electron Density Determination of Mixed‐Valent Tetraphosphetes
Authors: Breuers Verena , Lehmann Christian W. , Frank Walter 
Published: February 2015

AbstractFive dispirocyclic λ3,λ5‐tetraphosphetes [{R2Si(NR1)(NR2)P2}2] (R1= R2and R1≠ R2) are easily prepared in almost quantitative yields via photolysis of the respective bis(trimethylsilyl)phosphanyldiazaphosphasiletidines with intense visible light. These deep‐yellow low‐coordinate phosphorus compounds can be considered as the first higher congeners of the well‐known cyclodiphosphazenes. The tetraphosphetes are remarkably stable in air and show unexpected molecular properties related to the unique bonding situation of the central four‐π‐electron four‐membered phosphorus ring. The extent of rhombic distortion of the central P4ring is remarkable due to an unusually acute angle at the σ2‐phosphorus atoms. All of the PP bonds are approximately equal in length. The distances are in the middle of the range given by phosphorus single and double bonds. The anisotropic absorption of visible light that can easily be observed in the case of the yellow/colorless dichroic crystals of [{Me2Si(NtBu)(NtBu)P2}2] and the exceptional31P NMR chemical shift of the σ2‐phosphorus atoms are the most remarkable features of the λ3,λ5‐tetraphosphetes. In the case of [{Me2Si(NtBu)(NtBu)P2}2], the Hansen–Coppens multipole model is applied to extract the electron density from high‐resolution X‐ray diffraction data obtained at 100 K. Static deformation density and topological analysis reveal a unique bonding situation in the central unsaturated P4fragment characterized by polar σ‐bonding, pronounced out‐of‐ring non‐bonding lone pair density on the σ2‐phosphorus atoms, and an additional non‐classical three‐center back‐bonding contribution.
Gold‐Catalyzed Tandem Hydroamination/Formal Aza‐Diels–Alder Reaction of Homopropargyl Amino Esters: A Combined Computational and Experimental Mechanistic Study
Authors: Miró Javier , Sánchez‐Roselló María , González Javier , del Pozo Carlos , Fustero Santos 
Published: February 2015

AbstractA tandem gold‐catalyzed hydroamination/formal aza‐Diels–Alder reaction is described. This process, which employs quaternary homopropargyl amino ester substrates, leads to the formation of an intrincate tetracyclic framework and involves the generation of four bonds and five stereocenters in a highly diastereoselective manner. Theoretical calculations have allowed us to propose a suitable mechanistic rationalization for the tandem protocol. Additionally, by studying the influence of the ligands on the rate of the gold‐catalyzed reactions, it was possible to establish optimum conditions in which to perform the process with a variety of substituents on the amino ester substrates. Notably, the asymmetric version of the tandem reaction was also evaluated.
Gold–Acetonyl Complexes: From Side‐Products to Valuable Synthons
Authors: Gasperini Danila , Collado Alba , Goméz‐Suárez Adrián , Cordes David B. , Slawin Alexandra M. Z. , Nolan Steven P. 
Published: February 2015

AbstractA new synthetic strategy was devised leading to the formation of complexes, such as [Au(IPr)(CH2COCH3)]. The approach capitalizes on the formation of a decomposition product observed in the course of the synthesis of [Au(IPr)(Cl)]. A library of gold acetonyl complexes containing the most common N‐heterocyclic carbene (NHC) ligands has been synthesized. These acetonyl complexes are good synthons for the preparation of numerous organogold complexes. Moreover, they have proven to be precatalysts in common gold(I)‐catalyzed reactions.
Mechanism of Phosphine Borane Deprotection with Amines: The Effects of Phosphine, Solvent and Amine on Rate and Efficiency
Authors: Lloyd‐Jones Guy C. , Taylor Nicholas P. 
Published: February 2015

AbstractThe kinetics of borane transfer from simple tertiary phosphine borane adducts to a wide range of amines have been determined. All data obtained, including second‐order kinetics, lack of cross‐over, and negative entropies of activation for reaction of triphenylphosphine borane with quinuclidine and triethylamine, are consistent with a direct (SN2‐like) transfer process, rather than a dissociative (SN1‐like) process. The identities of the amine, phosphine, and solvent all impact substantially on the rate (k) and equilibrium (K) of the transfer, which in some cases vary by many orders of magnitude. P‐to‐N transfer is more efficient with cyclic amines in apolar solvents due to reduced entropic costs and ground‐state destabilisation. Taken as a whole, the data allow informed optimisation of the deprotection step from the stand‐point of rate, or synthetic convenience. In all cases, both reactants should be present at high initial concentration to gain kinetic benefit from the bimolecularity of the process. Ultimately, the choice of amine is dictated by the identity of the phosphine borane complex. Aryl‐rich phosphine boranes are sufficiently reactive to allow use of diethylamine or pyrrolidine as a volatile low polarity solvent and reactant, whereas more alkyl‐rich phosphines benefit from the use of more reactive amines, such as 1,4‐diaza[2.2.2]bicyclooctane (DABCO), in apolar solvents at higher temperatures.
Synthesis of Mesoporous Wall‐Structured TiO2 on Reduced Graphene Oxide Nanosheets with High Rate Performance for Lithium‐Ion Batteries
Authors: Zhen Mengmeng , Sun Meiqing , Gao Guandao , Liu Lu , Zhou Zhen 
Published: February 2015

AbstractMesoporous wall‐structured TiO2 on reduced graphene oxide (RGO) nanosheets were successfully fabricated through a simple hydrothermal process without any surfactants and annealed at 400 °C for 2 h under argon. The obtained mesoporous structured TiO2–RGO composites had a high surface area (99 0307 m2 g−1) and exhibited excellent electrochemical cycling (a reversible capacity of 260 mAh g−1 at 1.2 C and 180 mAh g−1 at 5 C after 400 cycles), demonstrating it to be a promising method for the development of high‐performance Li‐ion batteries.
Restriction of Molecular Twisting on a Gold Nanoparticle Surface
Authors: Debnath Tushar , Dana Jayanta , Maity Partha , Lobo Hyacintha , Shankarling Ganapati S. , Ghosh Hirendra N. 
Published: February 2015

AbstractTo understand the photophysical properties of intramolecular charge transfer (ICT) and twisted intramolecular charge transfer (TICT) states on a gold nanoparticle (Au NP) surface, we have designed and synthesized a new coumarin molecule (C3) that exists both as ICT and TICT states in its excited state in a polar environment. On a Au NP surface, an excited C3 molecule only exists as an ICT state owing to restricted molecular rotation of a diethylamino group; as a result, no conversion from the ICT to TICT state was observed. Selection of the preferential state of a molecule with dual emitting states can be helpful for selected biological applications.
Cycloelimination of Imidazolidin‐2‐ylidene N‐Heterocyclic Carbenes: Mechanism and Insights into the Synthesis of Stable “NHC‐CDI” Amidinates
Authors: Zhukhovitskiy Aleksandr V. , Geng Julie , Johnson Jeremiah A. 
Published: February 2015

AbstractWe report the discovery that 1,3‐bis(aryl)imidazolidin‐2‐ylidenes, one of the most widely studied classes of N‐heterocyclic carbenes (NHCs), undergo quantitative conversion to zwitterionic “NHC‐CDI” amidinates upon heating to ≈100 °C in solution. The mechanism of this novel NHC decomposition process is studied in detail. These studies enabled the rational synthesis of a new class of bench stable amidinates from a panel of NHCs and carbodiimides. We expect these constructs to find utility in a variety of applications.
Homocatenation of Aluminum: Alkane‐like Structures of Li2Al2H6 and Li3Al3H8
Authors: Gish J. Tyler , Popov Ivan A. , Boldyrev Alexander I. 
Published: February 2015

AbstractA new class of aluminum homocatenated compounds (LinAlnH2n+2) is proposed based on quantum chemical calculations. In these compounds, Al abstracts an electron from Li, becoming valence isoelectronic with C, Si, and Ge, thus mimicking respective structural features of Group 14 hydrides. Using the Coalescence Kick search program coupled with density functional theory calculations, we investigated the potential energy surfaces of Li2Al2H6 and Li3Al3H6. Then single‐point‐energy coupled‐cluster calculations were performed for the lowest energy structures found. Indeed, the global minima established for Li2Al2H6 and Li3Al3H6 contain the Al2H62− and Al3H63− kernels, which are isostructural with ethane (C2H6), disilane (Si2H6), digermane (Ge2H6) and propane (C3H8), trisilane (Si3H8), trigermane (Ge3H8) molecules, respectively. Structural, energetic, and electronic characteristics of the Li2Al2H6 and Li3Al3H8 compounds are presented and the viability of their synthesis is discussed.
Single Oxygen‐Atom Insertion into PB Bonds: On‐ and Off‐Metal Transformation of a Borylphosphine into a Borylphosphinite
Authors: Bailey Jonathan A. , Sparkes Hazel A. , Pringle Paul G. 
Published: February 2015

AbstractAn oxygen atom is selectively inserted into the PB bond of a borylphosphine (L1) by reaction with Me3NO to afford the corresponding borylphosphinite (L2). This transformation can also be effected when L1 is coordinated to rhodium. The ν(CO) values for trans‐[RhCl(CO)(L)2] reveal very different electronic properties for coordinated L1 and L2 which translate into the strikingly different performances of the complexes [RhCl(L)(cod)] (L= L1 or L2, cod=1,5‐cyclooctadiene) in hydrosilylation and hydroboration catalysis.
Improved transformation‐based quantile regression
Authors: Geraci Marco , Jones M. C. 
Published: February 2015

AbstractModelling the quantiles of a random variable is facilitated by their equivariance to monotone transformations. In conditional modelling, transforming the response variable serves to approximate nonlinear relationships by means of flexible and parsimonious models; these usually include standard transformations as special cases. Transforming back to obtain predictions on the original scale or to calculate marginal nonlinear effects becomes a trivial task. This approach is particularly useful when the support of the response variable is bounded. We propose novel transformation models for singly or doubly bounded responses, which improve upon the performance of conditional quantile estimators as compared to other competing transformations, namely the Box–Cox and the Aranda‐Ordaz transformations. The key is to provide flexible transformations with range the whole of the real line. Estimation is carried out by means of a two‐stage estimator, while confidence intervals are obtained by bootstrap. A simulation study and some illustrative data analyses are presented.The Canadian Journal of Statistics43: 118–132; 2015 © 2015 Statistical Society of Canada
A simple model‐based approach to variable selection in classification and clustering
Authors: Partovi Nia Vahid , Davison Anthony C. 
Published: February 2015

AbstractClustering and classification of replicated data is often performed using classical techniques that inappropriately treat the data as unreplicated, or by complex modern ones that are computationally demanding. In this paper, we introduce a simple approach based on a “spike‐and‐slab” mixture model that is fast, automatic, allows classification, clustering and variable selection in a single framework, and can handle replicated or unreplicated data. Simulation shows that our approach compares well with other recently proposed methods. The ideas are illustrated by application to microarray and metabolomic data. The Canadian Journal of Statistics 43: 157–175; 2015 © 2015 Statistical Society of Canada