bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amorphous Silicon: New Insights into an Old Material
Authors: Spomer Natalie , Holl Sven , Zherlitsyna Larissa , Maysamy Fariba , Frost Andreas , Auner Norbert 
Published: February 2015

AbstractAmorphous silicon is synthesized by treating the tetrahalosilanes SiX4 (X=Cl, F) with molten sodium in high boiling polar and non‐polar solvents such as diglyme or nonane to give a brown or a black solid showing different reactivities towards suitable reagents. With regards to their technical relevance, their stability towards oxygen, air, moisture, chlorine‐containing reaction partners RCl (R=H, Cl, Me) and alcohols is investigated. In particular, reactions with methanol are a versatile tool to deliver important products. Besides tetramethoxysilane formation, methanolysis of silicon releases hydrogen gas under ambient conditions and is thus suitable for a decentralized hydrogen production; competitive insertion into the MeOH versus the MeOH bond either yields H‐ and/or methyl‐substituted methoxy functional silanes. Moreover, compounds, such as MenSi(OMe)4−n (n=0–3) are simply accessible in more than 75 % yield from thermolysis of, for example, tetramethoxysilane over molten sodium. Based on our systematic investigations we identified reaction conditions to produce the methoxysilanes MenSi(OMe)4−n in excellent (n=0:100 %) to acceptable yields (n=1:51 %; n=2:27 %); the yield of HSi(OMe)3 is about 85 %. Thus, the methoxysilanes formed might possibly open the door for future routes to silicon‐based products.
Layer‐by‐Layer Assemblies of Catechol‐Functionalized TiO2 Nanoparticles and Porphyrins through Electrostatic Interactions
Authors: Burger Alexandra , Costa Rubén D. , Lobaz Volodymyr , Peukert Wolfgang , Guldi Dirk M. , Hirsch Andreas 
Published: February 2015

AbstractIn the current work, we present the successful functionalization and stabilization of P‐25 TiO2 nanoparticles by means of N1,N7‐bis(3‐(4‐tert‐butyl‐pyridium‐methyl)phenyl)‐4‐(3‐(3‐(4‐tert‐butyl‐pyridinium‐methyl)phenylamino)‐3‐oxopropyl)‐4‐(3,4‐dihydroxybenzamido)heptanediamide tribromide (1). The design of the latter is aimed at nanoparticle functionalization and stabilization with organic building blocks. On one hand, 1 features a catechol anchor to enable its covalent grafting onto the TiO2 surface, and on the other hand, positively charged pyridine groups at its periphery to prevent TiO2 agglomeration through electrostatic repulsion. The success of functionalization and stabilization was corroborated by thermogravimetric analysis, dynamic light‐scattering, and zeta potential measurements. As a complement to this, the formation of layer‐by‐layer assemblies, which are governed by electrostatic interactions, by alternate deposition of functionalized TiO2 nanoparticles and two negatively charged porphyrin derivatives, that is, 5,10,15,20‐(phenoxyacetic acid)‐porphyrin (2) and 5,10,15,20‐(4‐(2‐ethoxycarbonyl)‐4‐(2‐phenoxyacetamido)heptanedioic acid)‐porphyrin (3), is documented. To this end, the layer‐by‐layer deposition is monitored by UV/Vis spectroscopy, scanning electron microscopy, ellipsometry, and profilometry techniques. The resulting assemblies are utilized for the construction and testing of novel solar cells. From stable and repeatable photocurrents generated during several “on‐off” cycles of illumination, we derive monochromatic incident photo‐to‐current conversion efficiencies of around 3 %.
Nanocomposite Made of an Oligo(p‐phenylenevinylene)‐Based Trihybrid Thixotropic Metallo(organo)gel Comprising Nanoscale Metal–Organic Particles, Carbon Nanohorns, and Silver Nanoparticles
Authors: Bhattacharjee Subham , Samanta Suman K. , Moitra Parikshit , Pramoda K. , Kumar Ram , Bhattacharya Santanu , Rao C. N. R. 
Published: February 2015

AbstractA silver ion (Ag+)‐triggered thixotropic metallo(organo)gel of p‐pyridyl‐appended oligo(p‐phenylenevinylene) derivatives (OPVs) is reported for the first time. Solubilization of single‐walled carbon nanohorns (SWCNHs) in solutions of the pure OPVs as well as in the metallogels mediated by π–π interactions has also been achieved. In situ fabrication of silver nanoparticles (AgNPs) in the SWCNH‐doped dihybrid gel leads to the formation of a trihybrid metallogel. The mechanical strength of the metallogels could be increased stepwise in the order: freshly prepared gel<dihybrid gel<trihybrid gel. Microscopic studies of the trihybrid gel indicate the formation of three distinct morphologies, that is, nanoscale metal–organic particles (NMOPs), flowerlike aggregates of SWCNHs and AgNPs, and also their integration with each other. Detailed studies suggest lamellar organizations of the linear metal–ligand complexes in the NMOPs, which upon association create a three‐dimensional network that eventually immobilizes the solvent molecules.
Induced Folding of Protein‐Sized Foldameric β‐Sandwich Models with Core β‐Amino Acid Residues
Authors: Olajos Gábor , Hetényi Anasztázia , Wéber Edit , Németh Lukács J. , Szakonyi Zsolt , Fülöp Ferenc , Martinek Tamás A. 
Published: February 2015

AbstractThe mimicry of protein‐sized β‐sheet structures with unnatural peptidic sequences (foldamers) is a considerable challenge. In this work, the de novo designed betabellin‐14 β‐sheet has been used as a template, and α→β residue mutations were carried out in the hydrophobic core (positions 12 and 19). β‐Residues with diverse structural properties were utilized: Homologous β3‐amino acids, (1R,2S)‐2‐aminocyclopentanecarboxylic acid (ACPC), (1R,2S)‐2‐aminocyclohexanecarboxylic acid (ACHC), (1R,2S)‐2‐aminocyclohex‐3‐enecarboxylic acid (ACEC), and (1S,2S,3R,5S)‐2‐amino‐6,6‐dimethylbicyclo[3.1.1]heptane‐3‐carboxylic acid (ABHC). Six α/β‐peptidic chains were constructed in both monomeric and disulfide‐linked dimeric forms. Structural studies based on circular dichroism spectroscopy, the analysis of NMR chemical shifts, and molecular dynamics simulations revealed that dimerization induced β‐sheet formation in the 64‐residue foldameric systems. Core replacement with (1R,2S)‐ACHC was found to be unique among the β‐amino acid building blocks studied because it was simultaneously able to maintain the interstrand hydrogen‐bonding network and to fit sterically into the hydrophobic interior of the β‐sandwich. The novel β‐sandwich model containing 25 % unnatural building blocks afforded protein‐like thermal denaturation behavior.
Tris‐Functionalized Hybrid Anderson Polyoxometalates: Synthesis, Characterization, Hydrolytic Stability and Inversion of Protein Surface Charge
Authors: Blazevic Amir , Al‐Sayed Emir , Roller Alexander , Giester Gerald , Rompel Annette 
Published: February 2015

AbstractSingle‐ and double‐sided functionalized hybrid organic–inorganic Anderson polyoxomolybdates with GaIII and FeIII positioned as central heteroatoms have been synthesized in a mild, two‐step synthesis in an aqueous medium. Compounds 1–4 were isolated as hydrated salts, [TBA]3[GaMo6O18(OH)3{(OCH2)3CCH2OH}]×12 H2O (1) (TBA=tetrabutylammonium), Na3[FeMo6O18{(OCH2)3CCH2OH}2]×11 H2O (2), [TMA]2[GaMo6O18(OH)3{(OCH2)3CNH3}]×7 H2O (3) (TMA=tetramethylammonium), and Na[TMA]2[FeMo6O18(OH)3{(OCH2)3CNH3}](OH)×6 H2O (4). All the compounds were characterized based on single‐crystal X‐ray diffraction (SXRD), FTIR, UV/Vis, thermogravimetric, ESI‐MS, NMR, and elemental analyses. Compound 1 was also crystallized with two smaller organic cations, giving [TMA]3[GaMo6O18(OH)3{(OCH2)3CCH2OH}]×n H2O (5) and [GDM]3[GaMo6O18(OH)3{(OCH2)3CCH2OH}]×n H2O (6) (GDM=guanidinium) and were characterized based on UV/Vis, NMR, FTIR, and elemental analyses. The use of these compounds as additives in macromolecular crystallography was investigated by examining their hydrolytic stability by using ESI‐MS in a pH range of 4 to 9. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) analysis showed that BSA remains intact in a solution containing up to 100 equivalents of 1 or 4 over more than four days at 20 °C. Zeta potential measurements demonstrate that 1–4 induce charge inversions on the positively charged surface of BSA (1 mg mL−1) with concentrations starting as low as 1.29 mM for compounds 1 and 2, which have the highest negative surface charge.
Towards the Discrimination of Carboxylates by Hydrogen‐Bond Donor Anion Receptors
Authors: Kadam Sandip A. , Martin Kerli , Haav Kristjan , Toom Lauri , Mayeux Charly , Pung Astrid , Gale Philip A. , Hiscock Jennifer R. , Brooks Simon J. , Kirby Isabelle L. , Busschaert Nathalie , Leito Ivo 
Published: February 2015

AbstractThe binding constants (log Kass) of small synthetic receptor molecules based on indolocarbazole, carbazole, indole, urea and some others, as well as their combinations were measured for small carboxylate anions of different basicity, hydrophilicity and steric demands, that is, trimethylacetate, acetate, benzoate and lactate, in 0.5 % H2O/[D6]DMSO by using the relative NMR‐based measurement method. As a result, four separate binding affinity scales (ladders) including thirty‐eight receptors were obtained with the scales anchored to indolocarbazole. The results indicate that the binding strength is largely, but not fully, determined by the strength of the primary hydrogen‐bonding interaction. The latter in turn is largely determined by the basicity of the anion. The higher is the basicity of the anion the stronger in general is the binding, leading to the approximate order of increasing binding strength, lactate<benzoate<acetate≤trimethylacetate, which holds with all investigated receptors. Nevertheless, there are a number of occasions when the binding order changes with changing of the carboxylate anion, sometimes quite substantially. Principal component analysis (PCA) reveals that this is primarily connected to preferential binding of trimethylacetate, supposedly caused by an additional hydrophobic/solvophobic interaction. These findings enable making better predictions, which receptor framework or cavity is best suited for carboxylate anions in receptor design.
A Ferrocenyl Kaleidoscope: Slow Interconversion of Six Diastereo‐atropisomers of 2,6‐Di‐tert‐butyl‐9,10‐diferrocenyltriptycene
Authors: Nikitin Kirill , Muldoon Jimmy , Müller‐Bunz Helge , McGlinchey Michael J. 
Published: February 2015

AbstractThe title triptycene, 6, has been isolated as the product of 9,10‐cycloaddition of benzyne to 9,10‐diferrocenyl‐2,6‐di‐tert‐butylanthracene, 5, whose X‐ray crystal structure is reported. Each ferrocenyl unit in 6 has access to the same three non‐equivalent molecular environments, and their rotations relative to the molecular paddlewheel give rise to six slowly interconverting atropisomers. Their dynamic behaviour in solution is a challenging NMR puzzle that can be successfully solved by taking advantage of the recently described very large diamagnetic anisotropy of the ferrocenyl moiety, together with the C2 symmetry of particular atropisomers. Application of one‐ and two‐dimensional NMR techniques over a range of temperatures together, with a detailed analysis of the homo‐ and heteronuclear correlations in 6, resulted in unequivocal mapping of the 99 1H and 162 13C positions in the six interconverting systems. Variable‐temperature 2D‐EXSY measurements revealed that, while the stability of the atropisomers is almost identical, they are separated by energy barriers which the ferrocenyls must overcome in the course of their interconversions. The heights of two different rotational barriers have been identified and these experimental findings are in good agreement with DFT calculations.
A Single‐Ion Magnet Based on a Heterometallic CoIII2DyIII Complex
Authors: Goura Joydeb , Brambleby Jamie , Goddard Paul , Chandrasekhar Vadapalli 
Published: February 2015

AbstractWe report a CoIII2DyIII complex, which shows single‐ion‐magnet behaviour. AC susceptibility data of this compound reveals the presence of slow relaxation of the magnetization in zero‐field below 15 K. The relaxation barrier is 88 K.
One‐Pot Synthesis of O‐Allylhydroxylamines through the Organocatalytic Oxidation of Tertiary Allylic Amines Followed by a [2,3]‐Meisenheimer Rearrangement
Authors: Theodorou Alexis , Limnios Dimitris , Kokotos Christoforos G. 
Published: February 2015

AbstractA cheap, green, and highly efficient one‐pot method for the synthesis of O‐protected allylic alcohols is described. By utilizing 2,2,2‐trifluoroacetophenone as the organocatalyst and H2O2 as the oxidant, a variety of allylic amine N‐oxides were synthesized, which upon heating are converted to the final products through a [2,3]‐Meisenheimer rearrangement.
Generation of Pseudocontact Shifts in Proteins with Lanthanides Using Small “Clickable” Nitrilotriacetic Acid and Iminodiacetic Acid Tags
Authors: Loh Choy‐Theng , Graham Bim , Abdelkader Elwy H. , Tuck Kellie L. , Otting Gottfried 
Published: February 2015

AbstractPseudocontact shifts (PCS) induced by paramagnetic lanthanide ions provide unique long‐range structural information in nuclear magnetic resonance (NMR) spectra, but the site‐specific attachment of lanthanide tags to proteins remains a challenge. Here we incorporated p‐azido‐phenylalanine (AzF) site‐specifically into the proteins ubiquitin and GB1, and ligated the AzF residue with alkyne derivatives of small nitrilotriacetic acid and iminodiacetic acid tags using the CuI‐catalysed “click” reaction. These tags form lanthanide complexes with no or only a small net charge and produced sizeable PCSs with paramagnetic lanthanide ions in all mutants tested. The PCSs were readily fitted by single magnetic susceptibility anisotropy tensors. Protein precipitation during the click reaction was greatly alleviated by the presence of 150 mM NaCl.
Synthetic Studies on Actinorhodin and γ‐Actinorhodin: Synthesis of Deoxyactinorhodin and Deoxy‐γ‐actinorhodin/Crisamicin A Isomer
Authors: Mulay Sandip V. , Fernandes Rodney A. 
Published: February 2015

AbstractA strategy based on bidirectional Dötz benzannulation and the oxa‐Pictet–Spengler reaction toward the synthesis of actinorhodin and γ‐actinorhodin has been explored. This work has resulted in the synthesis of deoxyactinorhodin and deoxy‐γ‐actinorhodin. The latter is a regioisomer of crisamicin A (which has 10,10′‐dihydroxy groups).
Iridium‐Catalyzed Intermolecular Dehydrogenative Silylation of Polycyclic Aromatic Compounds without Directing Groups
Authors: Murai Masahito , Takami Keishi , Takai Kazuhiko 
Published: February 2015

AbstractThis study describes the iridium‐catalyzed intermolecular dehydrogenative silylation of C(sp2)H bonds of polycyclic aromatic compounds without directing groups. The reaction produced various arylsilanes through both SiH and CH bond activation, with hydrogen as the sole byproduct. Reactivity was affected by the electronic nature of the aromatic compounds, and silylation of electron‐deficient and polycyclic aromatic compounds proceeded efficiently. Site‐selectivity was controlled predominantly by steric factors. Therefore, the current functionalization proceeded with opposite chemo‐ and site‐selectivity compared to that observed for general electrophilic functionalization of aromatic compounds.
Ultrasensitive Biosensing Platform Based on the Luminescence Quenching Ability of Plasmonic Palladium Nanoparticles
Authors: Li Hui , Sun De‐en , Liu Zhihong 
Published: February 2015

AbstractAn ultrasensitive biosensing platform for DNA and protein detection is constructed based on the luminescence quenching ability of plasmonic palladium nanoparticles (PdNPs). By growing the particles into large sizes (ca. 30 nm), the plasmonic light absorption of PdNPs is broadened and extended to the visible range with extinction coefficients as high as 109 L mol−1 cm−1, enabling complete quenching of fluorescent dyes that emit at diverse ranges and that are tagged to bioprobes. Meanwhile the nonspecific quenching of the dyes (not bound to probes) is negligible, leading to extremely low background signal. Utilizing the affinity of PdNPs towards bioprobes, such as single‐stranded (ss) DNA and polypeptide molecules, which is mainly assigned to the coordination interaction, nucleic acid assays with a quantification limit of 3 pM target DNA and protein assay are achieved with a simple mix‐and‐detect strategy based on the luminescence quenching‐and‐recovery protocol. This is the first demonstration of biosensing employing plasmonic absorption of nanopalladium, which offers pronounced sensing performances and can be reasonably expected for wide applications.
Einsatz eines Ultraschall‐Durchflussmessgerätes zur Regelung des Volumenstroms in der Hochgradienten‐Magnetseparation
Authors: Shaikh Yonas S. , Schussmann Stefan , Lieblang Michael , Kampeis Percy 
Published: February 2015

AbstractBei der Verwendung der Hochgradienten‐Magnetseparation (HGMS) in der Bioverfahrenstechnik werden meist Schlauchpumpen zur Förderung eingesetzt. Bei konstanter Drehzahl der Pumpe fällt allerdings der Volumenstrom durch den HGMS‐Filter mit der Zeit ab, weil mit zunehmender Filterbeladung der freie Strömungsquerschnitt immer weiter eingeengt wird. Daraus resultiert, dass die Beladung des HGMS‐Filters zeitlich nicht konstant erfolgt. In der vorliegenden Untersuchung wurde der Einsatz eines Ultraschall‐Durchflussmessgeräts für die dynamische Anpassung der Pumpendrehzahl zur Konstanthaltung des Volumenstroms während der Magnetseparation erprobt.
Numerical Simulation of the Role of Dayside Magnetic Reconnection in Polar Cap Patch Formation
Authors: Sheng‐Gao YANG , Bei‐Chen ZHANG , Qing‐He ZHANG , Han‐Xian FANG , Jun‐Ming LIU , Xiao‐Lin ZHOU , Jian‐Bin ZHANG 
Published: February 2015

AbstractAs a significant polar space weather phenomenon, the polar cap patch formation is one of the important research subjects. Observations suggest that the strong convection flow due to the dayside magnetic reconnection has a “breaking off” effect on the TOI (Tongue of ionization), as a result the polar cap patch is formed. However, the auroral particles precipitation increases the F region electron density, which will block the “breaking off” effect. Based on a self‐consistent model of polar ionosphere, this paper simulated the F region plasma density evolution under the combined effect of soft precipitation and electric field. The results show that when local electric field is more than 80 mV·m−1, the “breaking off” occurs effectively. Also, we analyzed the evolution of various plasma parameters in the process of the “breaking off”, and discussed its internal physical mechanism.
The Improved Anisotropy Normalized Variance for Detecting Non‐Vertical Magnetization Anomalies
Authors: Heng‐Lei ZHANG , Marangoni Y. R. , Ren‐Guang ZUO , Xiang‐Yun HU 
Published: February 2015

AbstractFor the magnetic field with unknown magnetization direction, it is necessary to study the edge detection for the magnetic source of oblique magnetization directly. In this study, we propose a new edge detection called anisotropy normalized variance based on magnetic gradient tensor (ANV_MGT). First we use an anisotropy scale to improve the core function of ANV to show the effect of the anisotropy Gaussian function. Then the magnetic gradient tensor mode is used in the ANV method to process the anomalies with oblique magnetization. We construct a numerical model of complex magnetic anomalies with an oblique magnetization, which is used to test the edge detection method. The model test shows that the proposed method, ANV_MGT, can detect the edge of the magnetic source with non‐vertical magnetization direction. It also shows that the proposed method is better than application of ANV on the 3D analytic signal amplitude. In the application to real data from western China, a perfect magnetite ore location is determined by performing ANV_MGT for the non‐reduction to the pole data.
Computer‐Guided Design, Synthesis, and Biological Evaluation of Quinoxalinebisarylureas as FLT3 Inhibitors
Authors: Göring Stefan , Bensinger Dennis , Naumann Eva C. , Schmidt Boris 
Published: February 2015

AbstractActivating mutations of FMS‐like tyrosine kinase 3 (FLT3) are present in ∼30 % of patients with acute myeloid leukemia (AML) and are associated with poor prognosis. Point mutations in the tyrosine kinase domain (TKD) are observed as primary mutations or are acquired as secondary mutations in FLT3 with internal tandem duplications (ITDs) after treatment with tyrosine kinase inhibitors (TKIs). Although dozens of potent inhibitors against FLT3 ITD have been reported, activating TKD point mutations, especially at residues F691 and D835, remain the leading cause for therapy resistance, highlighting the consistent need for new potent inhibitors. Herein we report the identification and characterization of novel quinoxaline‐based FLT3 inhibitors. We used the pharmacophore features of diverse known inhibitors as a starting point for a new optimization algorithm for type II TKIs, starting from an in silico library pharmacophore search and induced‐fit docking in the known FLT3 structure. This led to the design of a set of diverse quinoxalinebisarylureas, which were profiled in an FLT3 kinase activity assay. The most promising compounds were further evaluated in a zebrafish embryo phenotype assay.
When do we need to care about the caregiver? Supportive care needs, anxiety, and depression among informal caregivers of patients with cancer and cancer survivors
Authors: Sklenarova Halina , Krümpelmann Arne , Haun Markus W. , Friederich Hans‐Christoph , Huber Johannes , Thomas Michael , Winkler Eva C. , Herzog Wolfgang , Hartmann Mechthild 
Published: February 2015

BACKGROUNDCancer not only affects patients but also their caregivers. The objective of the current study was to assess the unmet needs of cancer caregivers and to identify possible predictors of their supportive care needs.METHODSIn a cross‐sectional survey, 188 dyads of patients diagnosed with lung, urological, or gastrointestinal cancer and their primary caregivers were recruited. Caregivers were asked to complete the Supportive Care Needs Survey self‐report questionnaire (for partners and caregivers); patients completed the corresponding questionnaire. Both groups provided information regarding their distress (National Comprehensive Cancer Network Distress Thermometer), anxiety, and depression (Patient Health Questionnaire‐4). Clinical characteristics were obtained from medical records.RESULTSThe mean age of the caregivers was 57.8 years. Approximately 72.3% were female. Patients had an average age of 62.5 years, with 33.0% being male. Caregivers were more distressed (P<.01) and exhibited higher anxiety scores (P<.01) compared with patients. Approximately 14.4% of caregivers reported no unmet need and 43.6% had at least 10 needs that were unmet. Main caregiver concerns were regarding health care service and information needs followed by emotional and psychological needs. To some degree, unmet needs in patients and caregivers' anxiety predicted unmet caregiver needs. Sociodemographic and clinical variables were not found to be significant predictors.CONCLUSIONSA substantial percentage of caregivers have unmet needs for support, mainly with regard to fears concerning the patient's condition, receiving disease‐related information, and emotional support for themselves. Prediction of unmet needs in caregivers from other clinical and psychological variables was rather poor. Therefore, by means of the frequency and disparity of caregivers unmet needs, they should be systematically assessed to direct specific offers. Cancer 2015;121:1513–1519. © 2015 American Cancer Society.