bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced Hydrolytic Stability of Siliceous Surfaces Modified with Pendant Dipodal Silanes
Authors: Arkles Barry , Pan Youlin , Larson Gerald L. , Singh Mani 
Published: July 2014

AbstractDipodal silanes possess two silicon atoms that can covalently bond to a surface. They offer a distinct advantage over conventional silanes commonly used for surface modification in terms of maintaining the integrity of surface coatings, adhesive primers, and composites in aqueous environments. New nonfunctional and functional dipodal silanes with structures containing “pendant” rather than “bridged” organofunctionality are introduced. The stability of surfaces in aqueous environments prepared from dipodal silanes with hydrophobic alkyl functionality is compared to the stability of similar surfaces prepared from the conventional silanes. In strongly acidic and brine environments, surfaces modified with dipodal silanes demonstrate markedly improved resistance to hydrolysis compared to surfaces prepared from conventional silanes. Pendant dipodal silanes exhibit greater stability than bridged dipodal silanes. The apparent equilibrium constant for the formation of silanol species by the hydrolysis of a disiloxane bond was determined as Kc=[SiOH]2/[Si‐O‐Si][H2O]=6±1×10−5 and is helpful in understanding the enhanced hydrolytic stability of surfaces modified with dipodal silanes.
Luminescent Hybrid Materials Based on Laponite Clay
Authors: Li Huanrong , Li Man , Wang Yu , Zhang Wenjun 
Published: July 2014

AbstractThe spectroscopic behavior of ionic Eu3+ or Tb3+ complexes of an aromatic carboxyl‐functionalized organic salt as well as those of the hybrid materials derived from adsorption of the ionic complexes on Laponite clay are reported. X‐ray diffraction (XRD) patterns suggest that the complexes are mainly adsorbed on the outer surfaces of the Laponite disks rather than intercalated within the interlayer spaces. Photophysical data showed that the energy‐transfer efficiency from the ligand to Eu3+ ions in the hybrid material is increased remarkably with respect to the corresponding ionic complex. The hybrid material containing the Eu3+ complex shows bright red emission from the prominent 5D0→7F2 transition of Eu3+ ions, and that containing the Tb3+ complex exhibits bright green emission due to the dominant 5D4→7F5 transition of Tb3+ ions.
Water Compatible Photoarylation of Amino Acids and Peptides
Authors: Sudakow Alex , Papke Uli , Lindel Thomas 
Published: July 2014

AbstractA novel photoarylation of amino acids and peptides is described, which tolerates the presence of water. Irradiation of Boc‐protected amino acids in the presence of N‐protected 2‐azidobenzimidazoles leads to selective arylation of carboxy termini or side chains. The new reaction also works for peptides. Irradiation of the nonapeptide H‐SPSYVYHQF‐OH also resulted in selective arylation of the tyrosine side chains, as indicated by ESI‐MS/MS fragmentation. Chemo‐ and regioselectivity could add the title reaction to the repertoire of photoaffinity labeling methods.
Stereoselective Hydrodehalogenation via a Radical‐Based Mechanism Involving T‐Shaped Chiral Nickel(I) Pincer Complexes
Authors: Rettenmeier Christoph , Wadepohl Hubert , Gade Lutz H. 
Published: July 2014

AbstractWe herein report the catalytic enantioselective hydrodehalogenation based on the interplay of a chiral molecular nickel(I)/nickel(II)hydride system. Prochiral geminal dihalogenides are dehalogenated via a secondary configurationally unstable, potentially metal‐stabilized radical intermediate. In a subsequent step, the liberated radical is then trapped by the nickel(II) hydrido complex, present in a large excess under the catalytic conditions, which in turn induces the enantioselectivity during the hydrogen atom transfer onto the radical intermediate. These new chiral nickel(I) complexes were found to catalyze the asymmetric hydrodehalogenation of geminal dihalogenides with moderate to good enantiomeric excess values using LiEt3BH as reductant. The main side product generally observed is the dehalogenated alkene, whereas the hydrodehalogenation of the chiral monohalogen compound occurred much more slowly despite the large excess of reductant.
Electronic Transitions in Conformationally Controlled Tetrasilanes with a Wide Range of SiSiSiSi Dihedral Angles
Authors: Tsuji Hayato , Fogarty Heather A. , Ehara Masahiro , Fukuda Ryoichi , Casher Deborah L. , Tamao Kohei , Nakatsuji Hiroshi , Michl Josef 
Published: July 2014

AbstractUnlike π‐electron chromophores, the peralkylated n‐tetrasilane σ‐electron chromophore resembles a chameleon in that its electronic spectrum changes dramatically as its silicon backbone is twisted almost effortlessly from the syn to the anti conformation (changing the SiSiSiSi dihedral angle ω from 0 to 180°). A combination of UV absorption, magnetic circular dichroism (MCD), and linear dichroism (LD) spectroscopy on conformationally controlled tetrasilanes 1–9, which cover fairly evenly the full range of angles ω, permitted a construction of an experimental correlation diagram for three to four lowest valence electronic states. The free chain tetrasilane n‐Si4Me10 (10), normally present as a mixture of three enantiomeric conformer pairs of widely different angles ω, has also been included in our study. The spectral trends are interpreted in terms of avoided crossings of 1B with 2B and 2A with 3A states, in agreement with SAC‐CI calculations on the excited states of 1–7 and conformers of 10.
Small Cycloalkane (CN)2CC(CN)2 Structures Are Highly Directional Non‐covalent Carbon‐Bond Donors
Authors: Bauzá Antonio , Mooibroek Tiddo J. , Frontera Antonio 
Published: July 2014

AbstractHigh‐level calculations (RI‐MP2/def2‐TZVP) disclosed that the σ‐hole in between two C atoms of cycloalkane X2CCX2 structures (X=F, CN) is increasingly exposed with decreasing ring size. The interacting energy of complexes of F−, HO−, N≡C−, and H2CO with cyclopropane and cyclobutane X2CCX2 derivatives was calculated. For X=F, these energies are small to positive, while for X=CN they are all negative, ranging from −6.8 to −42.3 kcal mol−1. These finding are corroborated by a thorough statistical survey of the Cambridge Structural Database (CSD). No clear evidence could be found in support of non‐covalent carbon bonding between electron‐rich atoms (El.R.) and F2CCF2 structures. In marked contrast, El.R.⋅⋅⋅(CN)2CC(CN)2 interactions are abundant and highly directional. Based on these findings, the hydrophobic electrophilic bowl formed by 1,1′,2,2′‐tetracyano cyclopropane or cyclobutane derivatives is proposed as a new and synthetically accessible supramolecular synthon.
Influences of Land Use/Land Cover on Hydrogeochemical Indexes of Karst Groundwater in the Dagouhe Basin, Southwest China
Authors: Lan Funing , Qin Xiaoqun , Jiang Zhongcheng , Meng Rongguo , Mo Risheng , Yang Shengmeng , Wang Wenjuan , An Shuqing 
Published: July 2014

AbstractIt is essential to understand how karst groundwater hydrogeochemistry responds to watershed land use and land cover changes. However, little information is available on this response in the karst region of southwest China. Water temperature, pH, electrical conductivity, total organic carbon (TOC), ions concentration, CO2 pressure (pCO2), calcite saturation index (SIC), stable carbon isotopic compositions of dissolved inorganic carbon (δ13CDIC), and carbon sink ability were monitored during the hydrological year of May 2010 to April 2011 in the eastern and western areas of Dagouhe Basin. The two areas share the same climatic condition but show different land use/land cover. Field data were used to calculate pCO2, SIC, and karst carbon sink density. The results showed higher ion concentrations, TOC, carbon sink ability, pCO2 and lower pH, SIC, δ13C in the groundwater of the eastern area than those in the western area. In the eastern area, there is larger forest and farmland coverage, both produced and kept more biological carbon sources and lower δ13C in the soil‐vadose zone. While in the western area, there is larger rocky land and wasteland coverage. All results suggested that land use and land cover pattern played very important roles in this basin. Therefore, the hydrogeochemical indexes selected could be good indicators for the land use/cover change in the studied basin.
6‐Hydroxybenzothiophene Ketones: Potent Inhibitors of 17β‐Hydroxysteroid Dehydrogenase Type 1 (17β‐HSD1) Owing to Favorable Molecule Geometry and Conformational Preorganization
Authors: Miralinaghi Parisa , Schmitt Christian , Hartmann Rolf W. , Frotscher Martin , Engel Matthias 
Published: July 2014

AbstractThe inhibition of 17β‐hydroxysteroid dehydrogenase type 1 (17β‐HSD1), which catalyzes the conversion of estrone into the potent estrogen receptor agonist estradiol (E2), is discussed as a novel therapeutic approach for the treatment of estrogen‐dependent diseases. Because the reduction of E2 would be basically limited to the target tissues, this approach is expected to cause fewer side effects than the currently employed antihormonal therapies. Recently, we reported on 6‐hydroxybenzothiazole ketones as a new class of 17β‐HSD1 inhibitors with a notable activity/selectivity profile. In an attempt to further optimize these parameters, we modified the benzothiazole core by a systematic bioisosteric replacement. Thus, we were able to identify a new 6‐hydroxybenzothiophene derivative that displayed stronger inhibition of 17β‐HSD1 (IC50=13 nM) and that was also more selective than a benzothiazole analog. Using ab initio calculations, we found that the higher potency of the 6‐hydroxybenzothiophene derivative was probably due to more favorable conformational preorganization of the scaffold for binding to the enzyme.
Design of a General‐Purpose European Compound Screening Library for EU‐OPENSCREEN
Authors: Horvath Dragos , Lisurek Michael , Rupp Bernd , Kühne Ronald , Specker Edgar , von Kries Jens , Rognan Didier , Andersson C. David , Almqvist Fredrik , Elofsson Mikael , Enqvist Per‐Anders , Gustavsson Anna‐Lena , Remez Nikita , Mestres Jordi , Marcou Gilles , Varnek Alexander , Hibert Marcel , Quintana Jordi , Frank Ronald 
Published: July 2014

AbstractThis work describes a collaborative effort to define and apply a protocol for the rational selection of a general‐purpose screening library, to be used by the screening platforms affiliated with the EU‐OPENSCREEN initiative. It is designed as a standard source of compounds for primary screening against novel biological targets, at the request of research partners. Given the general nature of the potential applications of this compound collection, the focus of the selection strategy lies on ensuring chemical stability, absence of reactive compounds, screening‐compliant physicochemical properties, loose compliance to drug‐likeness criteria (as drug design is a major, but not exclusive application), and maximal diversity/coverage of chemical space, aimed at providing hits for a wide spectrum of drugable targets. Finally, practical availability/cost issues cannot be avoided. The main goal of this publication is to inform potential future users of this library about its conception, sources, and characteristics. The outline of the selection procedure, notably of the filtering rules designed by a large committee of European medicinal chemists and chemoinformaticians, may be of general methodological interest for the screening/medicinal chemistry community. The selection task of 200K molecules out of a pre‐filtered set of 1.4M candidates was shared by five independent European research groups, each picking a subset of 40K compounds according to their own in‐house methodology and expertise. An in‐depth analysis of chemical space coverage of the library serves not only to characterize the collection, but also to compare the various chemoinformatics‐driven selection procedures of maximal diversity sets. Compound selections contributed by various participating groups were mapped onto general‐purpose self‐organizing maps (SOMs) built on the basis of marketed drugs and bioactive reference molecules. In this way, the occupancy of chemical space by the EU‐OPENSCREEN library could be directly compared with distributions of known bioactives of various classes. This mapping highlights the relevance of the selection and shows how the consensus reached by merging the five different 40K selections contributes to achieve this relevance. The approach also allows one to readily identify subsets of target‐ or target‐class‐oriented compounds from the EU‐OPENSCREEN library to suit the needs of the diverse range of potential users. The final EU‐OPENSCREEN library, assembled by merging five independent selections of 40K compounds from various expert groups, represents an excellent example of a Europe‐wide collaborative effort toward the common objective of building best‐in‐class European open screening platforms.
Lung cancer adrenal gland metastasis: Optimal fine‐needle aspirate and touch preparation smear cellularity characteristics for successful theranostic next‐generation sequencing
Authors: Gleeson Ferga C. , Kipp Benjamin R. , Levy Michael J. , Voss Jesse S. , Campion Michael B. , Minot Douglas M. , Tu Zheng J. , Klee Eric W. , Lazaridis Konstantinos N. , Kerr Sarah E. 
Published: July 2014

BACKGROUNDMultigene molecular testing to guide personalized therapy for oncology patients is of increasing clinical relevance. Molecular testing of fine‐needle aspiration samples is underused, but when acquired with minimally invasive techniques could become the standard of care to obtain theranostic specimens. The aims of the current study were to identify key cytology specimen selection criteria suitable for next‐generation sequencing (NGS) and to determine the prevalence and spectrum of pathogenic alterations in a cohort of patients with AJCC stage IV lung cancer.METHODSA total of 70 adrenal gland cytology specimens with direct smears were screened to identify 56 patients with a single slide containing at least 300 total cells and 20% tumor nuclei. After DNA extraction, the NGS protocols were used to simultaneously detect mutations in >2800 exonic regions in 50 key cancer genes.RESULTSA total of 28 specimens produced acceptable NGS results. Specimens with a combined critical cell mass (>5000 viable cells) and a DNA concentration >5 ng/µL resulted in a 95% chance of successful sequencing. A total of 37 pathogenic alterations were identified in 10 genes and in 25 patients (85%). A pathogenic alteration (≥1) linked to available or developing targeted therapies was revealed in 50% of cases.CONCLUSIONSThe data from the current study demonstrate that theranostic NGS can be applied to adrenal gland metastasis using routine cytologic smear specimens. The characteristics of such smears could be evaluated during onsite adequacy assessment by cytopathology professionals. This model greatly augments the opportunity for customized genotype‐directed therapy from minimally invasive techniques. Cancer (Cancer Cytopathol) 2014;122:822–832. © 2014 American Cancer Society.
Pharmacokinetic profile after multiple deltoid or gluteal intramuscular injections of paliperidone palmitate in patients with schizophrenia
Authors: Rossenu Stefaan , Cleton Adriaan , Hough David , Crauwels Herta , Vandebosch An , Berwaerts Joris , Eerdekens Marielle , Herben Virginie , De Meulder Marc , Remmerie Bart , Francetic Igor 
Published: July 2014

AbstractPaliperidone palmitate (PP) is a once‐monthly long‐acting injectable antipsychotic approved for the treatment of schizophrenia in many countries. To evaluate the different injection‐site options, we compared the pharmacokinetic profile of paliperidone after multiple injections of PP 100 mg eq. (156 mg of PP, equivalent to 100 mg of paliperidone) on days 1, 8, 36, and 64 into the deltoid (n = 24) or gluteal muscle (n = 25) in patients with schizophrenia. After four injections in the deltoid muscle, paliperidone exposure was higher for AUCτ and Cmax, compared with the gluteal muscle (geometric mean AUCτ‐based ratio: 120% [90% CI: 93.1–154.7%], and geometric mean Cmax‐based ratio: 130% [90% CI: 100.6–168.9%]). The mean [SD] fluctuation index was higher, with a larger interpatient variability, after deltoid‐injections (75.9% [30.9%]) than gluteal‐injections (58.5% [14.3%]). The median tmax was similar for both sites. PP was generally tolerable in patients, with more favorable local‐site tolerability for gluteal‐injection. In conclusion, to achieve therapeutic‐concentrations quickly, the first‐two injections of PP are best administered into the deltoid muscle, whereas thereafter maintenance‐injections can be administered either in the deltoid or gluteal muscle.
Failure‐resilient real‐time processing of health streams
Authors: Ericson Kathleen , Pallickara Shrideep , Anderson Charles W. 
Published: July 2014

SummaryThe ability to analyze streaming data in real time is vital in systems that process data from health sensors. These systems need to build and maintain state, as well as preserve this state during system failures. In this work, we introduce a fault‐tolerance scheme designed for the Granules stream processing system. We work with two distinct health stream datasets: thorax extension and electroencephalogram (EEG) signal analysis. We have developed a monitoring program to track trends in the thorax extension dataset and a classification system for the EEG dataset, which allows us to determine user intent from EEG signals. Using these two motivating applications, we have explored several approaches to fault tolerance through replication, developing a hybrid approach that is particularly suited to health streams. Copyright © 2014 John Wiley & Sons, Ltd.
Sodium Vanadium Oxide: A New Material for High‐Performance Symmetric Sodium‐Ion Batteries
Authors: Hartung Steffen , Bucher Nicolas , Nair Vivek Sahadevan , Ling Cheah Yan , Wang Yuxi , Hoster Harry E. , Srinivasan Madhavi 
Published: July 2014

AbstractRoom‐temperature sodium‐ion batteries have the potential to become the technology of choice for large‐scale electrochemical energy storage because of the high sodium abundance and low costs. However, not many materials meet the performance requirements for practical applications. Here, we report a novel sodium‐ion battery electrode material, Na2.55V6O16⋅0.6 H2O, that shows significant capacities and stabilities at high current rates up to 800 mA g−1. X‐ray photoelectron spectroscopy measurements are carried out to better understand the underlying reactions. Moreover, due to the different oxidation states of vanadium, this material can also be employed in a symmetric full cell, which would decrease production costs even further. For these full cells, capacity and stability tests are conducted using various cathode:anode mass ratios.
Bottom‐Up Hybridization: A Strategy for the Preparation of a Thermostable Polyoxometalate–Polymer Hybrid with Hierarchical Hybrid Structures
Authors: Tang Jing , Yu Wei , Hu Min‐Biao , Xiao Yu , Wang Xiao‐Gang , Ren Li‐Jun , Zheng Ping , Zhu Wen , Chen Yongming , Wang Wei 
Published: July 2014

AbstractA bottom‐up strategy for the preparation of hierarchical hybrid materials with good thermostability is reported. The hybrid molecule was constructed from a Wells–Dawson‐type polyoxometalate (POM) cluster and a poly(ethylene glycol) (PEG) chain through covalent‐bond formation. The large distinction between the POM cluster and PEG chain results in a microphase separation to form POM and PEG layers that further alternatively arrange into hybrid lamellae with a sub‐20 nm thickness. Then the hybrid lamellae could simultaneously organize into spherulitic superstructures. Because of this hierarchical structuring, strong electrostatic interactions between POM clusters are maximized within the POM layers. This gives rise to thermostability. Structurally, the hybrid lamellae and the superstructures are unchanged, even at 160 °C, and indeed the shear storage modulus of the hybrid material remains nearly constant within this same temperature range. This study demonstrates the concept of bottom‐up hybridization, in which rationally selecting building blocks, designing the hybrid molecule, and then manipulating hierarchical structures can generate thermostable hybrid materials.
Effect of Preparation Method and CuO Promotion in the Conversion of Ethanol into 1,3‐Butadiene over SiO2–MgO Catalysts
Authors: Angelici Carlo , Velthoen Marjolein E. Z. , Weckhuysen Bert M. , Bruijnincx Pieter C. A. 
Published: July 2014

AbstractSilica–magnesia (Si/Mg=1:1) catalysts were studied in the one‐pot conversion of ethanol to butadiene. The catalyst synthesis method was found to greatly influence morphology and performance, with materials prepared through wet‐kneading performing best both in terms of ethanol conversion and butadiene yield. Detailed characterization of the catalysts synthesized through co‐precipitation or wet‐kneading allowed correlation of activity and selectivity with morphology, textural properties, crystallinity, and acidity/basicity. The higher yields achieved with the wet‐kneaded catalysts were attributed to a morphology consisting of SiO2 spheres embedded in a thin layer of MgO. The particle size of the SiO2 catalysts also influenced performance, with catalysts with smaller SiO2 spheres showing higher activity. Temperature‐programmed desorption (TPD) measurements showed that best butadiene yields were obtained with SiO2–MgO catalysts characterized by an intermediate amount of acidic and basic sites. A Hammett indicator study showed the catalysts’ pKa value to be inversely correlated with the amount of dehydration by‐products formed. Butadiene yields could be further improved by the addition of 1 wt % of CuO as promoter to give butadiene yields and selectivities as high as 40 % and 53 %, respectively. The copper promoter boosts the production of the acetaldehyde intermediate changing the rate‐determining step of the process. TEM‐energy‐dispersive X‐ray (EDX) analyses showed CuO to be present on both the SiO2 and MgO components. UV/Vis spectra of promoted catalysts in turn pointed at the presence of cluster‐like CuO species, which are proposed to be responsible for the increased butadiene production.
A robust and efficient dynamic identity‐based multi‐server authentication scheme using smart cards
Authors: Chang Chin‐Chen , Cheng Ting‐Fang , Hsueh Wei‐Yuan 
Published: July 2014

SummaryIn single‐server architecture, one service is maintained by one server. If a user wants to employ multiple services from different servers, he/she needs to register with these servers and to memorize numerous pairs of identities and passwords corresponding to each server. In order to improve user convenience, many authentication schemes have been provided for multi‐server environment with the property of single registration. In 2013, Li et al. provided an efficient multi‐server authentication scheme, which they contended that it could resist several attacks. Nevertheless, we find that their scheme is sensitive to the forgery attack and has a design flaw. This paper presents a more secure dynamic identity‐based multi‐server authentication scheme in order to solve the problem in the scheme by Li et al. Analyses show that the proposed scheme can preclude several attacks and support the revocation of anonymity to handle the malicious behavior of a legal user. Furthermore, our proposed scheme has a lower computation and communication costs, which make it is more suitable for practical applications. Copyright © 2014 John Wiley & Sons, Ltd.