bluuebunny/crossref_metadata_2025_split huggingface dataset:
Folding stability modulation of the villin headpiece helical subdomain by 4‐fluorophenylalanine and 4‐methylphenylalanine
Authors: Hsu Wei‐Lin , Shih Ting‐Chia , Horng Jia‐Cherng 
Published: May 2015

ABSTRACTHP36, the helical subdomain of villin headpiece, contains a hydrophobic core composed of three phenylalanine residues (Phe47, Phe51, and Phe58). Hydrophobic effects and electrostatic interactions were shown to be the critical factors in stabilizing this core and the global structure. To assess the interactions among Phe47, Phe51, and Phe58 residues and investigate how they affect the folding stability, we implanted 4‐fluorophenylalanine (Z) and 4‐methylphenylalanine (X) into the hydrophobic core of HP36. We chemically synthesized HP36 and its seven variants including four single mutants whose Phe51 or Phe58 was replaced with Z or X, and three double mutants whose Phe51 and Phe58 were both substituted. Circular dichroism and nuclear magnetic resonance measurements show that the variants exhibit a native HP36 like fold, of which F51Z and three double mutants are more stable than the wild type. Molecular modeling provided detailed interaction energy within the phenylalanine residues, revealing that electrostatic interactions dominate the stability modulation upon the introduction of 4‐fluorophenylalanine and 4‐methylphenylalanine. Our results show that these two non‐natural amino acids can successfully tune the interactions in a relatively compact hydrophobic core and the folding stability without inducing dramatic steric effects. Such an approach may be applied to other folded motifs or proteins. © 2015 Wiley Periodicals, Inc. Biopolymers 103: 627–637, 2015.
Transcatheter, inflatable, and fully repositionable aortic valve: Preliminary results using a modified implantation technique
Authors: Kische Stephan , D'Ancona Giuseppe , Agma Hüseyin U. , Gürer Hakan , Ortak Jasmin , Elsässer Albrecht , Öner Alper , Ince Hüseyin 
Published: May 2015

ObjectivesWe present our experience with an inflatable, non‐metallic, fully retrievable, and repositionable transcatheter aortic valve [Direct Flow® Medical (DFM)] focusing on technical features adopted during implantation.BackgroundImplantation techniques of new generation percutaneous aortic valves are still developing and with experience implementations are described.MethodsThe “low pressure” (initial valve inflation at 4 ATM, lower than the recommended 12 ATM) and the “alternate aortic curve” techniques (initial valve pulling either from the wire running on the side of the inner or from the one on the outer aortic curve) are part of our modified protocol for DFM® implantation.ResultsForty‐two consecutive patients underwent TAVI with DFM. The “low pressure” technique was used in all patients. In 27 (64.3%) patients the bulkiest calcifications were on the inner aortic curve side, and an inner curve technique was used to initiate valve pulling toward the annular hinge point. In the remaining 15 (35.7%) patients, an outer curve technique was used. Neither pull‐through nor re‐valving was reported. Valve performance showed mean gradient of 8.9 mm Hg. Mild paravalvular leak was reported in seven (16%) patients. No one experienced moderate or severe aortic insufficiency. Thirty‐day mortality was 9.5% (4/42).ConclusionThe “low pressure technique” and the “alternate curve technique” guarantee an anatomy and patient tailored approach to achieve controlled and finely tuned valve seating. © 2015 Wiley Periodicals, Inc.
Being reasonable during coronary revascularization
Authors: Belardi Jorge A. , Albertal Mariano 
Published: May 2015

Key Points

The SYNTAX score is an angiographically based tool useful for clinical decision‐making prior to coronary revascularization.
The residual SYNTAX score (after angioplasty) is an independent predictor of clinical long‐term outcome in patients with complex coronary artery disease.
Both scores require functional lesion assessment.
Adding clinical risk factors to both scores enhances their performance.
Eliminate the sheath and maximize the working space: Sheathless transradial guiding catheters
Authors: Gilchrist Ian C. 
Published: May 2015

Key Points

Use of a sheathless 6.5‐F guide may provide an option for transradial access in patients with smaller radial arteries or in need of a larger diameter guide.
This sheathless system avoids many of the problems inherent in home‐made systems as it is hydrophilic coated and has a tight interface between components reducing vascular trauma on insertion.
Advantages of this system need to be weighed against its relative thermal instability for support, while its low‐resistance from hydrophilic coatings gives a different.
Correlation between Structural and Catalytic Properties of Copper Supported on Porous Alumina for the Ethanol Dehydrogenation Reaction
Authors: Cassinelli Wellington H. , Martins Leandro , Passos Aline R. , Pulcinelli Sandra H. , Rochet Amélie , Briois Valérie , Santilli Celso V. 
Published: May 2015

AbstractStructural and surface features of highly dispersed copper catalysts supported on hierarchical porous alumina were evaluated for the ethanol dehydrogenation reaction. The catalysts were prepared by incipient wetness impregnation of alumina obtained by a dual template sol–gel procedure. Structural characterizations provided evidence that the copper was highly dispersed on the alumina in the form of monomeric octahedral Cu2+ species adsorbed into an incomplete layer. A two‐step reduction was observed for the catalysts in a temperature range of 50–250 °C under H2/He flow. The temperature for onset of reduction and the percentage of Cu+ species formed upon activation were dependent on the Cu loading. At lower Cu loadings, the amount of Cu+ increased, leading to a slower and less complete reduction. Based on the apparent activation energy and turnover frequency, it could be concluded that Cu+ containing a mixture of Cu+/Cu0 results in a more efficient catalyst than Cu0 for the ethanol dehydrogenation reaction.
High‐Throughput Synthesis of Uniform Silver Seed Particles by a Continuous Microfluidic Synthesis Platform
Authors: Thiele Matthias , Knauer Andrea , Csáki Andrea , Mallsch Daniell , Henkel Thomas , Köhler Johann Michael , Fritzsche Wolfgang 
Published: May 2015

AbstractControlled silver particle geometries require at least a synthesis in two steps which strongly differ in their reaction kinetics. For the first step, the very fast seed formation, chaotic advection‐based micromixers are tested in combination with a batch reactor for the growth step. Nanoparticles with narrow size distribution and excellent shape uniformity can be prepared in large batches. To achieve a highly reproducible and homogeneous particle solution, a microfluidic system containing three different micromixers for optimal mixing of the chemical precursors is established, allowing stringent control of every synthesis step. The produced silver particles can be used as seeds for forming anisotropic particles. Their further potential is demonstrated by preparation of anisotropic silver triangles. The thus generated seed particles are better suited for growing to triangles than those from conventional batch synthesis.
Probing Ionic Crystals by the Invariom Approach: An Electron Density Study of Guanidinium Chloride and Carbonate
Authors: Nelyubina Yulia V. , Lyssenko Konstantin A. 
Published: May 2015

AbstractA comparative study of two guanidinium salts, chloride and carbonate, is carried out to test the performance of the invariom approach for ionic crystals. Although treating them as formed by isolated ions with no charge transfer between them, the invariom approach provides features of interionic contacts that are amazingly similar to those obtained from conventional charge density analysis of high‐resolution X‐ray diffraction data, thus emerging as an easy way towards reliable description of chemical bonding peculiarities in ionic crystals.
Highly Functionalized Cyclopentane Derivatives by Tandem Michael Addition/Radical Cyclization/Oxygenation Reactions
Authors: Holan Martin , Pohl Radek , Císařová Ivana , Klepetářová Blanka , Jones Peter G. , Jahn Ullrich 
Published: May 2015

AbstractDensely functionalized cyclopentane derivatives with up to four consecutive stereocenters are assembled by a tandem Michael addition/single‐electron transfer oxidation/radical cyclization/oxygenation strategy mediated by ferrocenium hexafluorophosphate, a recyclable, less toxic single‐electron transfer oxidant. Ester enolates were coupled with α‐benzylidene and α‐alkylidene β‐dicarbonyl compounds with switchable diastereoselectivity. This pivotal steering element subsequently controls the diastereoselectivity of the radical cyclization step. The substitution pattern of the radical cyclization acceptor enables a switch of the cyclization mode from a 5‐exo pattern for terminally substituted olefin units to a 6‐endo mode for internally substituted acceptors. The oxidative anionic/radical strategy also allows efficient termination by oxygenation with the free radical 2,2,6,6‐tetramethyl‐1‐piperidinoxyl, and two CC bonds and one CO bond are thus formed in the sequence. A stereochemical model is proposed that accounts for all of the experimental results and allows the prediction of the stereochemical outcome. Further transformations of the synthesized cyclopentanes are reported.
Encapsulation of LnIII Ions/Dyes within a Microporous Anionic MOF by Post‐synthetic Ionic Exchange Serving as a LnIII Ion Probe and Two‐Color Luminescent Sensors
Authors: Zhao Shu‐Na , Song Xue‐Zhi , Zhu Min , Meng Xing , Wu Lan‐Lan , Feng Jing , Song Shu‐Yan , Zhang Hong‐Jie 
Published: May 2015

AbstractA new anionic framework {[Me2NH2]0.125[In0.125(H2L)0.25]⋅xDMF}n (1) with one‐dimensional (1D) channels along the c axis of about 13.06×13.06 Å2, was solvothermally synthesized and well characterized. Post‐synthetic cation exchange of 1 with Eu3+, Tb3+, Dy3+, Sm3+ afforded lanthanide(III)‐loaded materials, Ln3+@1, with different luminescent behavior, indicating that compound 1 could be used as a potential luminescent probe toward different lanthanide(III) ions. Additionally, compound 1 exhibits selective adsorption ability toward cationic dyes. Moreover, the RhB@1 realized the probing of different organic solvent molecules by tuning the energy transfer efficiency between two different emissions, especially for sensing DMF. This work highlights the practical application of luminescent guest@MOFs as sensors, and it paves the way toward other one/multi‐color luminescent host–guest systems by rational selection of MOF hosts and guest chromophores with suitable emissive colors and energy levels.
Carboxylate Assisted Ni‐Catalyzed CH Bond Allylation of Benzamides
Authors: Barsu Nagaraju , Kalsi Deepti , Sundararaju Basker 
Published: May 2015

AbstractA one‐step synthetic method was developed for allylation of benzamides using Ni(COD)2/RCO2H and [Ni(μ‐H2O)(OOCCMe3)2(HOOCCMe3)2]2 (A′) catalytic system. Efficient, well‐defined, air and moisture‐stable Ni–pivalate complex was isolated and employed in catalytic allylation. The influence of solvent on product selectivity was also investigated.
Carboxylate‐Driven Supramolecular Assemblies of Protonated meso‐Aryl‐Substituted Dipyrrolylpyrazoles
Authors: Maeda Hiromitsu , Chigusa Kengo , Yamakado Ryohei , Sakurai Tsuneaki , Seki Shu 
Published: May 2015

AbstractDipyrrolylpyrazole (dpp) derivatives possessing an aryl ring at the pyrazole 4‐position were synthesized. Upon protonation, modified dpp derivatives formed a variety of assembled structures through complexation with carboxylates, as observed by single‐crystal X‐ray and synchrotron XRD analyses. In particular, the complexation of protonated dpp species possessing long alkyl chains with dicarboxylates resulted in highly ordered assembled structures, the packing modes of which as lamellar structures were controlled by the lengths of the spacer units between two carboxylate moieties. The charge‐carrier transporting properties of the solid materials were also controlled by bound anions, including dicarboxylates.
Copper–Carbene Intermediates in the Copper‐Catalyzed Functionalization of OH Bonds
Authors: Pereira Ana , Champouret Yohan , Martín Carmen , Álvarez Eleuterio , Etienne Michel , Belderraín Tomás R. , Pérez Pedro J. 
Published: May 2015

AbstractCopper–carbene [TpxCuC(Ph)(CO2Et)] and copper–diazo adducts [TpxCu{η1‐N2C(Ph)(CO2Et)}] have been detected and characterized in the context of the catalytic functionalization of OH bonds through carbene insertion by using N2C(Ph)(CO2Et) as the carbene source. These are the first examples of these type of complexes in which the copper center bears a tridentate ligand and displays a tetrahedral geometry. The relevance of these complexes in the catalytic cycle has been assessed by NMR spectroscopy, and kinetic studies have demonstrated that the N‐bound diazo adduct is a dormant species and is not en route to the formation of the copper–carbene intermediate.
Synthesis and Characterization of Far‐Red/NIR‐Fluorescent BODIPY Dyes, Solid‐State Fluorescence, and Application as Fluorescent Tags Attached to Carbon Nano‐onions
Authors: Bartelmess Juergen , Baldrighi Michele , Nardone Valentina , Parisini Emilio , Buck David , Echegoyen Luis , Giordani Silvia 
Published: May 2015

AbstractA series of π‐extended distyryl‐substituted boron dipyrromethene (BODIPY) derivatives with intense far‐red/near‐infrared (NIR) fluorescence was synthesized and characterized, with a view to enhance the dye’s performance for fluorescence labeling. An enhanced brightness was achieved by the introduction of two methyl substituents in the meso positions on the phenyl group of the BODIPY molecule; these substituents resulted in increased structural rigidity. Solid‐state fluorescence was observed for one of the distyryl‐substituted BODIPY derivatives. The introduction of a terminal bromo substituent allows for the subsequent immobilization of the BODIPY fluorophore on the surface of carbon nano‐onions (CNOs), which leads to potential imaging agents for biological and biomedical applications. The far‐red/NIR‐fluorescent CNO nanoparticles were characterized by absorption, fluorescence, and Raman spectroscopies, as well as by thermogravimetric analysis, dynamic light scattering, high‐resolution transmission electron microscopy, and confocal microscopy.
Liquid‐Phase Synthesis of 2′‐Methyl‐RNA on a Homostar Support through Organic‐Solvent Nanofiltration
Authors: Gaffney Piers R. J. , Kim Jeong F. , Valtcheva Irina B. , Williams Glynn D. , Anson Mike S. , Buswell Andrew M. , Livingston Andrew G. 
Published: May 2015

AbstractDue to the discovery of RNAi, oligonucleotides (oligos) have re‐emerged as a major pharmaceutical target that may soon be required in ton quantities. However, it is questionable whether solid‐phase oligo synthesis (SPOS) methods can provide a scalable synthesis. Liquid‐phase oligo synthesis (LPOS) is intrinsically scalable and amenable to standard industrial batch synthesis techniques. However, most reported LPOS strategies rely upon at least one precipitation per chain extension cycle to separate the growing oligonucleotide from reaction debris. Precipitation can be difficult to develop and control on an industrial scale and, because many precipitations would be required to prepare a therapeutic oligonucleotide, we contend that this approach is not viable for large‐scale industrial preparation. We are developing an LPOS synthetic strategy for 2′‐methyl RNA phosphorothioate that is more amenable to standard batch production techniques, using organic solvent nanofiltration (OSN) as the critical scalable separation technology. We report the first LPOS‐OSN preparation of a 2′‐Me RNA phosphorothioate 9‐mer, using commercial phosphoramidite monomers, and monitoring all reactions by HPLC, 31P NMR spectroscopy and MS.
Transitional Metal/Chalcogen Dependant Interactions of Hairpin DNA with Transition Metal Dichalcogenides, MX2
Authors: Loo Adeline Huiling , Bonanni Alessandra , Sofer Zdenek , Pumera Martin 
Published: May 2015

AbstractOwing to the attractive properties that transition metal dichalcogenides (TMDs) display, they have found recent application in the fabrication of biosensing devices. These devices involve the immobilization of a recognition element such as DNA onto the surface of TMDs. Therefore, it is imperative to examine the interactions between TMDs and DNA. Herein, we explore the effect of different transition metals (Mo and W) and chalcogens (S and Se) on the interactions between hairpin DNA and TMDs of both bulk and t‐BuLi exfoliated forms. We discovered that the interactions are strongly dependent on the metal/chalcogen composition in TMDs.
Analyses and techniques for phase noise reduction in CMOS Colpitts oscillator topology
Authors: Chlis Ilias , Pepe Domenico , Zito Domenico 
Published: May 2015

SummaryThis paper reports the analyses of three techniques for phase noise reduction in the complementary metal‐oxide semiconductor (CMOS) Colpitts oscillator circuit topology. Namely, the three techniques are inductive degeneration, noise filter, and optimum current density. The design of the circuit topology is carried out in 28‐nm bulk CMOS technology. The analytical expression of the oscillation frequency is derived and validated through circuit simulations. Moreover, the theoretical analyses of the three techniques are carried out and verified by means of circuit simulations within a commercial design environment. The results obtained for the inductive degeneration and noise filter show the existence of an optimum inductance for minimum phase noise. The results obtained for the optimum bias current density technique applied to a Colpitts oscillator circuit topology incorporating either inductive degeneration or noise filter show the existence of an optimum bias current density for minimum phase noise. Overall, the analyses show that the adoption of these techniques may lead to a potential phase noise reduction up to 19 dB at a 1‐MHz frequency offset for an oscillation frequency of 10 GHz. © 2015 The Authors International Journal of Circuit Theory and Applications Published by John Wiley & Sons Ltd.
Planar and Nonplanar Shock Waves in a Degenerate Quantum Plasma
Authors: Ema S. A. , Hossen M. R. , Mamun A. A. 
Published: May 2015

AbstractThe nonlinear propagation of modified electron‐acoustic (mEA) shock waves in an unmagnetized, collisionless, relativistic, degenerate quantum plasma (containing non‐relativistic degenerate inertial cold electrons, both nonrelativistic and ultra‐relativistic degenerate hot electron and inertial positron fluids, and positively charged static ions) has been investigated theoretically. The well‐known Burgers type equation has been derived for both planar and nonplanar geometry by employing the reductive perturbation method. The shock wave solution has also been obtained and numerically analyzed. It has been observed that the mEA shock waves are significantly modified due to the effects of degenerate pressure and other plasma parameters arised in this investigation. The properties of planar Burgers shocks are quite different from those of nonplanar Burgers shocks. The basic features and the underlying physics of shock waves, which are relevant to some astrophysical compact objects (viz. non‐rotating white dwarfs, neutron stars, etc.), are briefly discussed. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Aberrant NK cell associated marker (CD56 and CD57) expression in chronic lymphocytic leukemia
Authors: Dorwal Pranav , Mehra Simmi , Pande Amit , Jain Dharmendra , Smeeta G. , Sachdev Ritesh , Raina Vimarsh 
Published: May 2015

BackgroundChronic lymphocytic leukemia (CLL) is one of the commonest leukemias that has been reported extensively throughout the literature. The characteristic phenotype includes co‐expression of CD5 and CD23, along with dim expression of light chain and CD22/CD79b, with lack of FMC7. The immunophenotypic scoring system given by Matutes has been used to differentiate CLL from non‐CLL chronic lymphoproliferative disorders. Various aberrancies have been described in CLL cases, including abnormal (dim or bright) expression of B cell markers and lineage infidel T cell, myelomonocytic, or rarely Natural killer (NK) cells markers. However, the aberrant co‐expression of CD56 and CD57 has not yet been reported.Method and ResultsWe hereby report a case of 62‐year female with a typical CLL phenotype and Matutes score of 5, showing the expression of CD56 and CD57.ConclusionThis entity may represent a rare subtype of CLL which needs to be studied more extensively for its prognostic implications. This is the first report of CLL with aberrant CD56 and CD57 expression. © 2015 International Clinical Cytometry Society
Canonical wnt signaling is required for commissural axon guidance
Authors: Avilés Evelyn C. , Stoeckli Esther T. 
Published: May 2015

ABSTRACTMorphogens have been identified as guidance cues for postcrossing commissural axons in the spinal cord. Shh has a dual effect on postcrossing commissural axons: a direct repellent effect mediated by Hhip as a receptor, and an indirect effect by shaping a Wnt activity gradient. Wnts were shown to be attractants for postcrossing commissural axons in both chicken and mouse embryos. In mouse, the effects of Wnts on axon guidance were concluded to depend on the planar cell polarity (PCP) pathway. Canonical Wnt signaling was excluded based on the absence of axon guidance defects in mice lacking Lrp6 which is an obligatory coreceptor for Fzd in canonical Wnt signaling. In the loss‐of‐function studies reported here, we confirmed a role for the PCP pathway in postcrossing commissural axon guidance also in the chicken embryo. However, taking advantage of the precise temporal control of gene silencing provided by in ovo RNAi, we demonstrate that canonical Wnt signaling is also required for proper guidance of postcrossing commissural axons in the developing spinal cord. Thus, axon guidance does not seem to depend on any one of the classical Wnt signaling pathways but rather involve a network of Wnt receptors and downstream components. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 190–208, 2016
Differentiation potential of individual olfactory c‐Kit+ progenitors determined via multicolor lineage tracing
Authors: Goss Garrett M. , Chaudhari Nirupa , Hare Joshua M. , Nwojo Raphael , Seidler Barbara , Saur Dieter , Goldstein Bradley J. 
Published: May 2015

ABSTRACTOlfactory tissue undergoes lifelong renewal, due to the presence of basal neural stem cells. Multiple categories of globose basal stem cells have been identified, expressing markers such as Lgr5, Ascl1, GBC‐2, and c‐Kit. The differentiation potential of individual globose cells has remained unclear. Here, we utilized Cre/loxP lineage tracing with a multicolor reporter system to define c‐Kit+ cell contributions at clonal resolution. We determined that reporter expression permitted identification of c‐Kit derived progeny with fine cellular detail, and that clones were found to be comprised by neurons only, microvillar cells only, microvillar cells and neurons, or gland/duct cells. Quantification of reporter‐labeled cells indicated that c‐Kit+ cells behave as transit amplifying or immediate precursors, although we also found evidence for longer‐term c‐Kit+ cell contributions. Our results from the application of multicolor fate mapping delineate the clonal contributions of c‐Kit+ cells to olfactory epithelial renewal, and provide novel insight into tissue maintenance of an adult neuroepithelium. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 241–251, 2016