bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histidine affinity chromatography‐based methodology for the simultaneous isolation ofEscherichia colismall and ribosomal RNA
Authors: Martins Rita , Queiroz João António , Sousa Fani 
Published: November 2011

ABSTRACTResearch on RNA has led to many important biological discoveries and the improvement of therapeutic technologies. In particular, there is a great focus on small RNA and ribosomal RNA owing to their key functions in the cell, which make them excellent therapeutic targets. Although the study of these RNA classes is progressing, some limitations have been found regarding the use of suitable techniques that are able to produce and isolate biologically competent and chemically stable RNA. To address this, we have developed a novel histidine affinity chromatography‐based isolation methodology for small and ribosomal RNA molecules. The new procedure involves three main steps: (1) cell lysis with guanidinium buffer, (2) RNA primary isolation with ammonium sulfate precipitation and (3) histidine affinity chromatography to specifically purify small RNA and ribosomal RNA from otherEscherichia coliimpurities (genomic DNA and proteins). The RNA quality assessment revealed that both RNA species were obtained with a high recovery, integrity and purity. The potential of this method to achieve a reproducible RNA isolation with appropriate quality has been demonstrated and it should have broad application in the structural, biophysical and biomedical investigation of systems involving RNA components. Copyright © 2011 John Wiley & Sons, Ltd.
Conformer‐Independent Ureidoimidazole Motifs—Tools to Probe Conformational and Tautomeric Effects on the Molecular Recognition of Triply Hydrogen‐Bonded Heterodimers
Authors: Pellizzaro Maria L. , McGhee Andrea M. , Renton Lisa C. , Nix Michael G. , Fisher Julie , Turnbull W. Bruce , Wilson Andrew J. 
Published: November 2011

AbstractLinear arrays of hydrogen bonds are useful for the reversible assembly of “stimuli‐responsive” supramolecular materials. There is thus an ongoing requirement for easy‐to‐synthesise motifs that are capable of presenting hydrogen‐bonding functionality in a predictable manner, such that high‐affinity and high‐fidelity recognition occurs. The design of linear arrays is made challenging as a consequence of their ability to adopt multiple conformational and tautomeric configurations; with each additional hydrogen‐bonding heteroatom added to an array, the available tautomeric and conformational space increases and it can be difficult to anticipate where unproductive conformers/tautomers will arise. This paper describes a detailed study on the complementary ureidoimidazole donor–donor–acceptor (DDA) array (1) and amidoisocytosine donor–acceptor–acceptor (DAA) array (2). A specific feature of 1 is that two degenerate, intramolecular hydrogen‐bonded conformations are postulated, both of which present a DDA array that is complementary to appropriate DAA partners. 1D and 2D 1H NMR spectroscopy, isothermal titration calorimetry, and ab initio structure calculations confirm 1 interacts with 2 (Ka≈33000 M−1 in CDCl3) in a conformer‐independent fashion driven by enthalpy. Comparison of the binding behaviour of 1 with hexylamidocytosine (4) and amidonaphthyridine (5) provides insight on the role that intramolecular hydrogen‐bonding plays in mediating affinity towards DAA partners.
3‐Azido‐N‐nitro‐1H‐1,2,4‐triazol‐5‐amine‐Based Energetic Salts
Authors: Wang Kai , Parrish Damon A. , Shreeve Jean'ne M. 
Published: November 2011

AbstractTwelve energetic nitrogen‐rich salts based on 3‐azido‐N‐nitro‐1H‐1,2,4‐triazol‐5‐amine were prepared and fully characterized by 1H, 13C NMR, and IR spectroscopy, differential scanning calorimetry (DSC), and elemental analysis. The crystal structures of the neutral compound 3‐azido‐N‐nitro‐1H‐1,2,4‐triazole‐5‐amine (1) and its triaminoguanidinium salt (13) were determined by single‐crystal X‐ray diffraction. The density of 1 and its twelve salts ranged from 1.57 to 1.79 g cm−3, and the heat of formation was calculated with the Gaussian 03 suite of programs. Compounds 1–13 exhibit promising detonation performances (pressure: 25.3–39.3 GPa; velocity: 8159–9409 ms−1; EXPLO 5.05). Impact sensitivities were also determined by hammer tests and resulted ranging from 2.5 J (very sensitive) to >40 J (insensitive).
Multi‐scale image segmentation algorithm based on support vector machine approximation criteria
Authors: Wang Liejun , Jia Zhenhong 
Published: November 2011

SUMMARYA new multi‐scale image segmentation algorithm based on support vector machine (SVM) approximation criteria has been discussed in this paper. Most current multi‐scale image segmentation algorithms are based on the restricted empirical risk minimization, and the approximation of multi‐scale image segmentation was poor. As the SVM theory was one based on the structural risk minimization, the best approximation results could be reached. So, it was combined with multi‐scale image segmentation algorithms, and one‐image multi‐resolution analysis approximation algorithms based on the SVM theory were presented in this paper, which could obtain more accurate multi‐scale image segmentation. By numerical results, the algorithm was further verified that more accurate image segmentation results were unfolded. Copyright © 2011 John Wiley & Sons, Ltd.
Computation of Hyperfine Tensors for Dinuclear MnIIIMnIV Complexes by Broken‐Symmetry Approaches: Anisotropy Transfer Induced by Local Zero‐Field Splitting
Authors: Schraut Johannes , Arbuznikov Alexei V. , Schinzel Sandra , Kaupp Martin 
Published: November 2011

AbstractBased on broken‐symmetry density functional calculations, the 55Mn hyperfine tensors of a series of exchange‐coupled, mixed‐valence, dinuclear MnIIIMnIV complexes have been computed. We go beyond previous quantum chemical work by fully including the effects of local zero‐field splitting (ZFS) interactions in the spin projection, following the first‐order perturbation formalism of Sage et al. [J. Am. Chem. Soc. 1989, 111, 7239]. This allows the ZFS‐induced transfer of hyperfine anisotropy from the MnIII site to the MnIV site to be described with full consideration of the orientations of local hyperfine and ZFS tensors. After scaling to correct for systematic deficiencies in the quantum chemically computed local ZFS tensors, good agreement with experimental 55Mn anisotropies at the MnIV site is obtained. The hyperfine coupling anisotropies on the MnIII site depend sensitively on structural distortions for a d4 ion. The latter are neither fully reproduced by using a DFT‐optimized coordination environment nor by using experimental structures. For very small exchange‐coupling constants, the perturbation treatment breaks down and a dramatic sensitivity to the scaling of the local ZFS tensors is observed. These results are discussed with respect to ongoing work to elucidate the structure of the oxygen‐evolving complex of photosystem II by analysis of the EPR spectra.
Polyglycerol‐Derived Amphiphiles for the Solubilization of Single‐Walled Carbon Nanotubes in Water: A Structure–Property Study
Authors: Popeney Chris S. , Setaro Antonio , Mutihac Radu‐Cristian , Bluemmel Pascal , Trappmann Britta , Vonneman Jonathan , Reich Stephanie , Haag Rainer 
Published: November 2011

AbstractA series of nonionic amphiphiles derived from polyglycerol dendrons were studied for their ability to solubilize and isolate single‐walled carbon nanotubes. The amphiphiles possessed differently sized polar head groups, hydrophobic tail units, and various aromatic and non‐aromatic groups between the head and tail groups. Absorbance analysis revealed that amphiphiles with anchor groups derived from pyrene were far inferior to those that possessed simple linear aliphatic tail groups. Absorbance and near‐infrared fluorescence analyses revealed a weak dependence on the dendron size of the head group, but a strong positive trend in suspended nanotube density and fluorescence intensity for amphiphiles with longer tail units. Variations in the moieties linking the head and tail groups led to a range of effects on the suspensions, with linkers imparting flexibility and a bent shape that gave improved performance overall. This was illustrated most dramatically by a pair of benzamide‐containing amphiphiles, the para isomer of which showed evidence in the fluorescence data of increased nanotube aggregate formation when compared with the meta isomer. In addition, statistical AFM was used to illustrate more directly the microscopic differences between amphiphiles that were effective at nanotube bundle disruption and those that were not.
Benchmarking Density Functional Methods against the S66 and S66x8 Datasets for Non‐Covalent Interactions
Authors: Goerigk Lars , Kruse Holger , Grimme Stefan 
Published: November 2011

AbstractDispersion‐corrected density functional theory is assessed on the new S66 and S66x8 benchmark sets for non‐covalent interactions. In total, 17 different density functionals are evaluated. Two flavors of our latest additive London‐dispersion correction DFT‐D3 and DFT‐D3(BJ), which differ in their short‐range damping functions, are tested. In general, dispersion corrections are again shown to be crucial to obtain reliable non‐covalent interaction energies and equilibrium distances. The corrections strongly diminish the performance differences between the functionals, and in summary most dispersion‐corrected methods can be recommended. DFT‐D3 and DFT‐D3(BJ) also yield similar results but for most functionals and intermolecular distances, the rational Becke–Johnson scheme performs slightly better. Particularly, the statistical analysis for S66x8, which covers also non‐equilibrium complex geometries, shows that the Minnesota class of functionals is also improved by the D3 scheme. The best methods on the (meta‐)GGA or hybrid‐ (meta‐)GGA level are B97‐D3, BLYP‐D3(BJ), PW6B95‐D3, MPW1B95‐D3 and LC‐ωPBE‐D3. Double‐hybrid functionals are the most accurate and robust methods, and in particular PWPB95‐D3 and B2‐PLYP‐D3(BJ) can be recommended. The best DFT‐D3 and DFT‐D3(BJ) approaches are competitive to specially adapted perturbation methods and clearly outperform standard MP2. Comparisons between S66, S22 and parts of the GMTKN30 database show that the S66 set provides statistically well‐behaved data and can serve as a valuable tool for, for example, fitting purposes or cross‐validation of other benchmark databases.
Cognitive Analytic Therapy for Borderline Personality Disorder: Therapist Competence and Therapeutic Effectiveness in Routine Practice
Authors: Kellett Stephen , Bennett Dawn , Ryle Tony , Thake Anna 
Published: November 2011

This study sought to examine the competency of cognitive analytic therapy (CAT) delivered under routine care conditions and to identify the effectiveness of CAT for patients with borderline personality disorder (BPD). Ten cognitive analytic therapists in six National Health Service Trust sites treated 19 patients with BPD using the standard CAT BPD contract of 24 sessions plus four follow‐ups. The methodology was small N repeated measures deign, with patients interviewed at the third follow‐up session using the Change Interview. Results indicate a high treatment and follow‐up compliance rate (89.47%). Significant reductions in psychological distress, risk and dissociation over the time course of the CAT occurred, with a significant increase in personality integration. Most sessions (92.85%) were delivered in a competent manner. Reductions to psychological distress occurred early in treatment and were sustained, whereas increases in personality integration typically occurred later on in treatment. Patients tended to attribute change to the therapy received. Benchmarking against extant CAT BPD evidence notes a moderate effect size across routine care and trial contexts. The results are discussed in terms of identified methodological shortcomings, clinical implications and the contribution made by the CAT model to the treatment of BPD. Copyright © 2011 John Wiley & Sons, Ltd.Key Practitioner MessageNarrative and diagrammatic reformulation in CAT offers the opportunity for early and effective engagement and potential symptomatic change in patients with BPD.It is possible to measure outcomes on a session‐by‐session manner with patients with BPD.Assessing fidelity to the treatment model is useful in practice‐based studies.
LTE and WiMAX: performance and complexity comparison for possible channel estimation techniques
Authors: Hafez H. , Fahmy Y.A. , Khairy M.M. 
Published: November 2011

SUMMARYThe similarities between the physical layer of LTE and WiMAX systems trigger the design of a unified hardware platform. As a consequence, there exists a great need to design common blocks that can be adapted to support both of them. In this paper, the choice of the channel estimator is studied where the performance and complexity trade‐off is investigated to seek a unified channel estimation design that can suit both systems under different channel conditions. The performance of different channel estimation techniques when applied to LTE and WiMAX systems is assessed and compared. Two channel profiles with different delay spreads are considered for urban macrocell and bad urban macrocell channels. Three different Doppler frequencies are assumed to illustrate the effect of users’ mobility. The estimators’ computational complexity is also thoroughly studied.Copyright © 2011 John Wiley & Sons, Ltd.
Arbitration Interframe Space‐controlled Medium Access Control: a medium access control protocol guaranteeing absolute priority in wireless local area networks
Authors: Lee Youngsoo , Lee Minsik , Choi Chong‐Ho 
Published: November 2011

SUMMARYThe demand for multimedia services, such as voice over Internet Protocol, video on demand, information dissemination, and ﬁle sharing, is increasing explosively in wireless local area networks. These multimedia services require a certain level of QoS. Thus, it is important to provide QoS for multimedia applications. IEEE 802.11e tries to meet the QoS requirement of multimedia services by using Enhanced Distributed Channel Access. This gives more weights to high‐priority traﬃc than low‐priority traﬃc in accessing the wireless channel. However, Enhanced Distributed Channel Access suffers from many problems such as low aggregate throughput, high collision rates, and ineffective QoS differentiation among priority classes. In this paper, we propose a new medium access scheme, the Arbitration Interframe Space‐controlled Medium Access Control (AC‐MAC), that guarantees absolute priority in 802.11 wireless networks. In AC‐MAC, the AIFS and contention window values are controlled, so that a higher‐priority traﬃc can preferentially access and effectively utilize the channel. Extensive simulations show that AC‐MAC can perfectly provide absolute priority and good throughput performance regardless of the number of contending nodes. In the simulation of voice over Internet Protocol service, AC‐MAC provides effective QoS differentiation among services and also meets the high level of QoS requirements. AC‐MAC also adapts quickly in a dynamic environment and provides good fairness among the nodes belonging to the same priority class. Copyright © 2011 John Wiley & Sons, Ltd.
Channel estimation for nonlinear MIMO receiver with square envelope detection
Authors: Hao Miin‐Jong , Tsai Yu‐Chi 
Published: November 2011

SUMMARYTwo practical channel estimation schemes, the moment‐based first‐and‐second moments and the simplified maximum likelihood estimators, are proposed for the MIMO/on–off keying system with square envelope detection applied for wireless sensor networks. Here, both the channel response and noise power are estimated simultaneously in comparison with other approaches in which the noise quantity is assumed to be known at the receiver. Hence, the developed estimators are more practical than those estimators without noise power estimation. Simulation results reveal that the system with both proposed schemes can achieve an excellent BER performance in a wide signal‐to‐noise ratio (SNR) range. More specifically, we observed that the simplified maximum likelihood estimator performed as well as the moment‐based first‐and‐second moments estimator for SNR greater than 7.5 dB, yet had much more decline at low SNRs. This study also investigated the effects of the numbers of receive antennas and transmit antennas on the system performance. Simulation results demonstrated that, at the BER of 10−3, the 5 × 5 system had an improvement of 7 dB in SNR compared with the 3 × 3 system. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis and Characterization of Nanocrystalline FeSb2 for Thermoelectric Applications
Authors: Datta Anuja , Nolas George S. 
Published: November 2011

AbstractWe report an ethanol‐mediated surfactant‐free solvothermal synthesis of phase‐pure Pnmm FeSb2 nanocrystals with an average size of 40 nm. The capping free growth of the nanocrystals resulted in the formation of inherent orthorhombic shapes. The nanocrystals were densified by spark plasma sintering to prepare a polycrystalline bulk material that consisted of 40–200 nm FeSb2 nanocrystal domains (nanocomposite). Low‐temperature Seebeck coefficient, resisitivity, and thermal conductivity were measured on parallelopipeds cut from the densified specimen and compared to bulk FeSb2 prepared by a solid‐state synthesis process. The FeSb2 nanocomposite showed a large reduction in lattice thermal conductivity relative to the bulk due to significant grain‐boundary phonon scattering. If one notes that the solution‐phase synthesis of Pnnm FeSb2 nanocrystals is accounted here for the first time and the low‐temperature thermoelectric properties indicates a significant reduction in lattice thermal conductivity for this material, this work represents an important step towards optimizing thermoelectric properties for cooling applications.
Photocatalytic H2 Production with a Rhenium/Cobalt System in Water under Acidic Conditions
Authors: Guttentag Miguel , Rodenberg Alexander , Kopelent René , Probst Benjamin , Buchwalder Christian , Brandstätter Marco , Hamm Peter , Alberto Roger 
Published: November 2011

AbstractIn photocatalytic H2 formation, tertiary amines are commonly used as sacrificial electron donors, thereby limiting the pH range for studies in water and the concentration of free protons. We found that ascorbate rapidly reductively quenches the excited state of [Re(CO)3(bipy)(py)]+ (bpy = 2,2′‐bipyridyl; py = pyridine). In combination with the water reduction catalyst (WRC) [Co{(DO)(DOH)pn}Br2] [(DO)(DOH)pn = N2,N2′‐propanediylbis(2,3‐butanedione 2‐imine 3‐oxime)], this system produces H2 upon irradiation with light under acidic conditions (pH range 2–6) and with significantly enhanced turnover numbers. Furthermore, we observed that, in contrast to similar systems with tertiary amines, oxidized ascorbate (dehydroascorbic acid) is slowly re‐reduced during the course of photocatalysis.
Triarylmethanols with Bulky Aryl Groups and the NOESY/EXSY Experimental Observation of a Two‐Ring‐Flip Mechanism for the Helicity Reversal of Molecular Propellers
Authors: Tormyshev Victor M. , Genaev Alexander M. , Sal'nikov Georgy E. , Rogozhnikova Olga Yu. , Troitskaya Tatiana I. , Trukhin Dmitry V. , Mamatyuk Victor I. , Fadeev Dmitry S. , Halpern Howard J. 
Published: November 2011

AbstractTriarylmethanols – the direct precursors of persistent trityl radicals – are racemic mixtures of chiral three‐bladed molecular propellers. Depending on the bulkiness of the aryl groups, they exhibit various tendencies to interconvert, and the half‐life of room‐temperature racemization varies between 8.4 h and 1.32 years. NOESY/EXSY experiments performed on two representative models strongly support the two‐ring flip mechanism for the configurational interchange.
1‐(Trifluoromethyl)cyclopent‐3‐enecarboxylic Acid Derivatives: Platforms for Bifunctional Cyclic Trifluoromethyl Building Blocks
Authors: Grellepois Fabienne , Kikelj Vincent , Coia Nicolas , Portella Charles 
Published: November 2011

AbstractWe report herein the synthesis and applications of 1‐(trifluoromethyl)cyclopent‐3‐ene‐1‐carboxylic acid and itsesters, promising new trifluoromethylated cyclic building blocks. Initially prepared starting from a pentafluorodithiopropanoic ester, a more convenient and effective approach has been developed starting from commercially available trifluoropropanoic acid or its methyl ester. The interest in these building blocks is exemplified by their use as platforms for a variety of difunctional trifluoromethylcyclopentane derivatives.
Axisymmetric magnetohydrodynamic flow of Jeffrey fluid over a rotating disk
Authors: Hayat T. , Nawaz M. , Awais M. , Obaidat S. 
Published: November 2011

SUMMARYThis paper examines the magnetohydrodynamic boundary layer flow of Jeffrey fluid due to a rotating disk. The governing partial differential equations are first transformed into the coupled system of ordinary differential equations and then solved by using the homotopy analysis method. The influence of various involved physical parameters on the dimensionless radial and azimuthal velocities is sketched and analyzed. The variation of skin friction coefficients in radial and azimuthal directions is studied for various values of pertinent parameters. Copyright © 2011 John Wiley & Sons, Ltd.
Altered neural activation in ornithine transcarbamylase deficiency during executive cognition: An fMRI study
Authors: Gropman Andrea L. , Shattuck Kyle , Prust Morgan J. , Seltzer Rebecca R. , Breeden Andrew L. , Hailu Ayichew , Rigas Amanda , Hussain Rehan , VanMeter John 
Published: November 2011

AbstractBackground: Ornithine transcarbamylase deficiency (OTCD) is an X‐linked urea cycle disorder characterized by hyperammonemia resulting in white matter injury and impairments in working memory and executive cognition. Objective: To test for differences in BOLD signal activation between subjects with OTCD and healthy controls during a working memory task. Design, setting and patients: Nineteen subjects with OTCD and 21 healthy controls participated in a case‐control, IRB‐approved study at Georgetown University Medical Center. Intervention: An N‐back working memory task was performed in a block design using 3T functional magnetic resonance imaging. Results: In subjects with OTCD we observed increased BOLD signal in the right dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) relative to healthy age matched controls. Conclusions: Increased neuronal activation in OTCD subjects despite equivalent task performance points to sub‐optimal activation of the working memory network in these subjects, most likely reflecting damage caused by hyperammonemic events. These increases directly relate to our previous finding of reduced frontal white matter integrity in the superior extents of the corpus callosum; key hemispheric connections for these areas. Future studies using higher cognitive load are required to further characterize these effects. Hum Brain Mapp, 2013. © 2011 Wiley Periodicals, Inc.