bluuebunny/crossref_metadata_2025_split huggingface dataset:
CaMg2P6O3N10 – A Quinary Oxonitridophosphate with an Unprecedented Tetrahedra Network Structure Type
Authors: Marchuk Alexey , Neudert Lukas , Oeckler Oliver , Schnick Wolfgang 
Published: June 2014

AbstractCaMg2P6O3N10 has been synthesized starting from stoichiometric amounts of Ca(N3)2, Mg3N2, P3N5, and PON in a high‐pressure/high‐temperature reaction at 8 GPa and 1100 °C. Adding small amounts of NH4Cl to the starting mixture afforded single crystals of CaMg2P6O3N10, which form transparent, colorless truncated octahedra. The crystal structure [space group I41/acd (no. 142), a = 12.494(1), c = 23.797(2) Å, Z = 16] was solved and refined by single‐crystal X‐ray diffraction analysis and confirmed by electron diffraction and transmission electron microscopy, including HRTEM image simulations. Rietveld refinement proved the phase purity of the product. FTIR analysis confirmed the absence N–H groups in the structure. Bond valence and lattice energy calculations (MAPLE) of the title compound are discussed. The crystal structure consists of polyhedral building units constructed from vertex‐sharing P(O,N)4 tetrahedra with condensed dreier and sechser rings.
A Decade of Dinuclear Technetium Complexes with Multiple Metal–Metal Bonds
Authors: Poineau Frederic , Forster Paul M. , Todorova Tanya K. , Johnstone Erik V. , Kerlin William M. , Gagliardi Laura , Czerwinski Kenneth R. , Sattelberger Alfred P. 
Published: June 2014

AbstractTransition metal complexes with multiple metal–metal bonds exhibit interesting catalytic and biological properties. One element whose metal–metal bond chemistry has been poorly studied is technetium. Currently, only 25 technetium complexes with multiple metal–metal bonds have been structurally characterized. The nature of metal–metal interactions in these complexes, as well as the influence of ligands on the bonding in the Tc2n+ unit (n = 6, 5, 4) are not well understood. In order to better understand the influence of ligands on the Tc–Tc bonding, a study of the solid‐state and electronic structure of dinuclear complexes with the Tc2n+ unit (n = 6, 5, 4) has been performed. Dinuclear technetium complexes (nBu4N)2Tc2X8, Tc2(O2CCH3)4X2, Tc2(O2CCH3)2Cl4, cesium salts of Tc2X83–, and Tc2X4(PMe3)4 (X = Cl, Br) were synthesized; their molecular and electronic structures, as well as their electronic absorption spectra, were studied by a number of physical and computational techniques. The structure and bonding in these systems have been investigated by using multiconfigurational quantum calculations. For all these complexes, the calculated geometries are in very good agreement with those determined experimentally. Bond order analysis demonstrates that all these complexes exhibit a total bond order of approximately 3. Analysis of individual effective bond order (EBO) components shows that these complexes have similar σ components, while the strength of their π components follows the order Tc2X4(PMe3)4 > Tc2X83– > Tc2(O2CCH3)2Cl4 > Tc2X82–. Calculations indicate that the δ components are the weakest bond in Tc2X8n– (n = 2, 3) and Tc2(O2CCH3)2Cl4. Further analysis of Tc2X83– and Tc2X4(PMe3)4 (X = Cl, Br) indicates that the electronic structure of the Tc25+ and Tc24+ units is insensitive to the nature of the coordinating ligands. The electronic absorption spectra of Tc2X8n– (n = 2, 3), Tc2(O2CCH3)2Cl4, and Tc2X4(PMe3)4 (X = Cl, Br) were studied in solution, and assignment of the transitions was performed by multiconfigurational quantum chemical calculations. For the Tc2X8n– (n = 2, 3; X = Cl, Br) anions and Tc2(O2CCH3)2Cl4, the lowest‐energy band is attributed to the δ→δ* transition. For Tc2X4(PMe3)4, the assignment of the transitions follow the following order in energy: δ*→σ* < δ*→π* < δ→σ* < δ→π*.
Structure Determination of Pentacyclic Pyridoacridine Alkaloids from the Australian Marine Organisms Ancorina geodides and Cnemidocarpa stolonifera
Authors: Tran Trong D. , Pham Ngoc B. , Quinn Ronald J. 
Published: June 2014

AbstractChemical investigation of two marine samples A. geodides and C. stolonifera led to the isolation of six pentacyclic pyridoacridine alkaloids, in which two compounds, ancorine A and cnemidine A, are new pyridoacridines. Their structures were determined by NMR spectroscopic analysis supported by quantum mechanical calculations of 13C NMR chemical shifts. This is the first study demonstrating that the pyridoacridine structure class can be assigned on the basis of quantum mechanical calculations. The isolated pyridoacridine alkaloids showed selective cytotoxicity against human prostate cancer cells (PC3) compared with human neonatal foreskin fibroblast noncancer cells (NFF).
A General Approach to N‐Heterocyclic Carbenes with a Fused Tetracyclic Core: Ligands for Suzuki–Miyaura Cross‐Coupling Reaction
Authors: Sutar Revannath L. , Kumar Vinod , Shingare Rahul D. , Thorat Shridhar , Gonnade Rajesh , Reddy D. Srinivasa 
Published: June 2014

AbstractThe synthesis of an N‐heterocyclic carbene (NHC) based on a tetracyclic scaffold by using simple, general, and scalable chemistry is disclosed. The developed route is suitable for introducing multiple substitutions on the tetracyclic scaffold. The utility of the present NHC as a ligand in the Suzuki–Miyaura cross‐coupling reaction is demonstrated with a low catalyst loading.
Biomimetic Synthesis of Functionalized γ‐Resorcylates from Dioxinone Derivatives
Authors: Blencowe Peter S. , Barrett Anthony G. M. 
Published: June 2014

AbstractBiomimetic syntheses of functionalized γ‐resorcylates from 2,2,6‐trimethyl‐4H‐1,3‐dioxin‐4‐one derivatives are reported. Cross metathesis of 2,2‐dimethyl‐6‐vinyl‐4H‐1,3‐dioxin‐4‐one with homoallylic esters or aldol reactions of tert‐butyl or benzyl esters with 1‐(2,2‐dimethyl‐4‐oxo‐4H‐1,3‐dioxin‐6‐yl)‐acetone and related ketones followed by aromatization under mild Appel‐type reaction conditions gave a range of γ‐resorcylates.
A Multiple Evaluation Approach of Commercially Available Screen‐Printed Nanostructured Carbon Electrodes
Authors: Grimaldi Aldana , Heijo Gonzalo , Méndez Eduardo 
Published: June 2014

AbstractCommercially available carbon‐based screen‐printed electrodes were studied by cyclic voltammetry and electrochemical impedance spectroscopy in their behavior towards electron transfer to the soluble fast redox probes hexacyanoferrate(III), hexaammineruthenium(III) and methyl‐viologen. Semi‐infinite linear diffusion was observed for hexacyanoferrate(III) probe, with heterogeneous electron transfer rate constants significantly favored on nanotubes‐modified surfaces. Finite diffusion was observed for methyl‐viologen on graphene electrodes, which was reflected in the enhancement of the faradic currents by 4‐folds. Hexaammineruthenium(III) showed mixed diffusion behavior. These characteristics are reflected in the voltammetric behavior of lead(II) and cadmium(II) stripping from in‐situ deposited bismuth layer.
The effect of various fire‐exposed surface dimensions on the spalling of concrete specimens
Authors: Werner Steve , Rogge Andreas 
Published: June 2014

SummaryConcrete spalling due to fire exposure is often defined as the sudden detachment of fragments from a concrete surface. It can be quantified by various parameters of which weight loss and spalling depth are the most common ones. The risk of spalling is influenced by many factors such as concrete composition, heating rate and applied testing methods. A reduced scale testing method should be developed to analyse the spalling behaviour and to understand its effectiveness in more detail. As a subsection of this development, this study aimed to analyse the effect of different‐sized, circular heated areas in semi full‐scale fire tests. Therefore, vermiculite slabs with varying cut‐outs in their centre were placed between a specimen made of a spalling‐sensitive concrete and the combustion chamber. The combustion chamber was heated following a standard fire curve. Our experimental results show that the thermal expansion inside of equal‐sized specimens is strongly dependent on the size of the heated area. In addition, this area also affects thermal stresses. They decrease as a result of lower temperature gradients for tests with smaller unheated boundary areas. Apart from this, the analysis of fragments shows no correlation between their relative volume distribution and the heated area. Copyright © 2014 John Wiley & Sons, Ltd.
Dynamic and Static Behavior of E–E' Bonds in Neutral and Charged Forms of HEE'H, MeEE'Me, andCyclo‐1,2‐EE'(CH2)3(E, E' = O, S, Se, and Te) Elucidated by AIM Dual Functional Analysis
Authors: Hayashi Satoko , Matsuiwa Kohei , Miza Hiroaki , Nakanishi Waro 
Published: June 2014

ABSTRACTThe nature of the E‐*‐E' bonds in neutral, monoanionic, monocationic, and dicationic forms of HEE'H (1), MeEE'Me (2), and cyclo‐1,2‐EE'(CH2)3(3) (E, E' = O, S, Se, Te) is investigated by applying AIM (atoms‐in‐molecules method) dual functional analysis. Hb(rc) are plotted versus Hb(rc) – Vb(rc)/2 for the data of E‐*‐E' at bond critical points (BCPs) of fully optimized structures and perturbed structures around the fully optimized ones. Plots for the fully optimized structures are analyzed by the polar coordinate (R, θ) representation. The (θp, κp) parameters are derived from those of the perturbed structures: θpcorresponds to the tangent line of each plot, and κpis the curvature. While (R, θ) correspond to the static nature, (θp, κp) represent the dynamic nature of interactions. The nature of E‐*‐E' in the neutral and charged species is classified by comparing their θ and θpvalues with those of the standard interactions as a reference. Data for E‐*‐E' in the neutral forms of1–3appear in the shared‐shell (SS) region (180° < θ), except for MeS‐*‐TeMe (2c), which does in the regular closed‐shell (CS) region (90° < θ < 180°). The E–E' bonds in the monoanionic forms of1–3become much longer and weakened. Therefore, data of the monoanionic forms appear in the regular CS. On the other hand, the strengths of E‐*‐E' in the mono‐ and dicationic forms are almost equal to those in the neutral forms of1–3in the plots, irrespective of the shorter E‐*‐E' lengths in the cationic forms, relative to the neutral forms.
Two‐dimensional and three‐dimensional computational models in hydrodynamic and morphodynamic reconstructions of a river bend: sensitivity and functionality
Authors: Kasvi Elina , Alho Petteri , Lotsari Eliisa , Wang Yunsheng , Kukko Antero , Hyyppä Hannu , Hyyppä Juha 
Published: June 2014

AbstractThis study assesses hydrodynamic and morphodynamic model sensitivity and functionality in a curved channel. The sensitivity of a depth‐averaged model to user‐defined parameters (grain size, roughness, transverse bed slope effect, transport relations and secondary flow) is tested. According to the sensitivity analysis, grain size, transverse bed slope effect and sediment transport relations are critical to simulated meander bend morphodynamics. The parametrization of grain size has the most remarkable effect: field‐based grain size parametrization is necessary in a successful morphodynamic reconstruction of a meander bend. The roughness parametrization method affects the distribution of flow velocities and therefore also morphodynamics. The combined effect of various parameters needs further research. Two‐dimensional (2D) and three‐dimensional (3D) reconstructions of a natural meander bend during a flood event are assessed against field measurements of acoustic Doppler current profiler and multi‐temporal mobile laser scanning data. The depth‐averaged velocities are simulated satisfactorily (differences from acoustic Doppler current profiler velocities 5–14%) in both 2D and 3D simulations, but the advantage of the 3D hydrodynamic model is unquestionable because of its ability to model vertical and near‐bed flows. The measured and modelled near‐bed flow, however, differed notably from each other's, the reason of which was left open for future research. It was challenging to model flow direction beyond the apex. The 3D flow features, which also affected the distribution of the bed shear stress, seem not to have much effect on the predicted morphodynamics: the 2D and 3D morphodynamic reconstructions over the point bar resembled each other closely. Although common features between the modelled and measured morphological changes were also found, some specific changes that occurred were not evident in the simulation results. Our results show that short‐term, sub‐bend scale morphodynamic processes of a natural meander bend are challenging to model, which implies that they are affected by factors that have been neglected in the simulations. The modelling of short‐term morphodynamics in natural curved channel is a challenge that requires further study. Copyright © 2014 John Wiley & Sons, Ltd.
Prostate Cancer Cells Preferentially Home to Osteoblast-rich Areas in the Early Stages of Bone Metastasis: Evidence From In Vivo Models
Authors: Wang Ning , Docherty Freyja E , Brown Hannah K , Reeves Kimberley J , Fowles Anne CM , Ottewell Penelope D , Dear T Neil , Holen Ingunn , Croucher Peter I , Eaton Colby L 
Published: June 2014

ABSTRACT

It has been suggested that metastasis-initiating cells gain a foothold in bone by homing to a metastastatic microenvironment (or “niche”). Whereas the precise nature of this niche remains to be established, it is likely to contain bone cell populations including osteoblasts and osteoclasts. In the mouse tibia, the distribution of osteoblasts on endocortical bone surfaces is non-uniform, and we hypothesize that studying co-localization of individual tumor cells with resident cell populations will reveal the identity of critical cellular components of the niche. In this study, we have mapped the distribution of three human prostate cancer cell lines (PC3-NW1, LN-CaP, and C4 2B4) colonizing the tibiae of athymic mice following intracardiac injection and evaluated their interaction with potential metastatic niches. Prostate cancer cells labeled with the fluorescent cell membrane dye (Vybrant DiD) were found by two-photon microscopy to be engrafted in the tibiae in close proximity (∼40 µm) to bone surfaces and 70% more cancer cells were detected in the lateral compared to the medial endocortical bone regions. This was associated with a 5-fold higher number of osteoblasts and 7-fold higher bone formation rate on the lateral endocortical bone surface compared to the medial side. By disrupting cellular interactions mediated by the chemokine (C-X-C motif) receptor 4 (CXCR4)/chemokine ligand 12 (CXCL12) axis with the CXCR4 inhibitor AMD3100, the preferential homing pattern of prostate cancer cells to osteoblast-rich bone surfaces was disrupted. In this study, we map the location of prostate cancer cells that home to endocortical regions in bone and our data demonstrate that homing of prostate cancer cells is associated with the presence and activity of osteoblast lineage cells, and suggest that therapies targeting osteoblast niches should be considered to prevent development of incurable prostate cancer bone metastases. © 2014 American Society for Bone and Mineral Research.
Sustained local delivery of oncolytic short hairpin RNA adenoviruses for treatment of head and neck cancer
Authors: Jung Se‐Hui , Choi Joung‐Woo , Yun Chae‐Ok , Yhee Ji Young , Price Robert , Kim Sun Hwa , Kwon Ick Chan , Ghandehari Hamidreza 
Published: June 2014

AbstractBackgroundOncolytic adenovirus (Ad)‐mediated gene therapy is a promising approach for suppression of primary tumors. Therapeutic efficacy of Ad‐mediated gene therapy has been limited by immunogenicity, rapid dissemination of viral progenies into systemic circulation and short duration of biological activity. Polymeric sustained local delivery can overcome many of these challenges to produce a viable therapy with improved outcomes.MethodsSilk‐elastinlike protein polymer (SELP) hydrogels were used for matrix‐mediated delivery of oncolytic Ad, containing short hairpin RNA (shRNA) targeted to C‐Met (sh‐C‐Met), to solid tumors in a nude mouse model of human head and neck cancer. The biological activity of Ad released from SELP hydrogels was examined as a function of time to investigate protective effects on viral activity. Antitumor efficacy and viral distribution were investigated for 3 weeks in tumor‐bearing mice.ResultsThe encapsulation of Ad with SELP hydrogels sustained biological activity longer than Ad alone. Ad in SELP matrix showed 1.5‐fold greater antitumor efficacy compared to that of naked Ad in human xenograft tumor models. Histological analysis demonstrated that treatment with Ad in a SELP matrix resulted in apoptosis in a wider area of tumor tissue and higher density of Ad infection compared to Ad administered alone.ConclusionsMatrix‐mediated delivery of Ad‐containing shRNA with SELP hydrogels enhances therapeutic efficacy by tumor‐selective infection, spatiotemporal control and preservation of biologic activity. Copyright © 2014 John Wiley & Sons, Ltd.
k‐Kings in k‐Quasitransitive Digraphs
Authors: Wang Ruixia , Meng Wei 
Published: June 2014

AbstractLet D be a digraph with vertex set and arc set . A vertex x is a k‐king of D, if for every , there is an ‐path of length at most k. A subset N of is k‐independent if for every pair of vertices , we have and ; it is l‐absorbent if for every there exists such that . A ‐kernel of D is a k‐independent and l‐absorbent subset of . A k‐kernel is a ‐kernel. A digraph D is k‐quasitransitive, if for any path of length k, x0 and are adjacent. In this article, we will prove that a k‐quasitransitive digraph with has a k‐king if and only if it has a unique initial strong component and the unique initial strong component is not isomorphic to an extended ‐cycle where each has at least two vertices. Using this fact, we show that every strong k‐quasitransitive digraph has a ‐kernel.
A decreased volume of the medial tibial spine is associated with an increased risk of suffering an anterior cruciate ligament injury for males but not females
Authors: Sturnick Daniel R. , Argentieri Erin C. , Vacek Pamela M. , DeSarno Michael J. , Gardner‐Morse Mack G. , Tourville Timothy W. , Slauterbeck James R. , Johnson Robert J. , Shultz Sandra J. , Beynnon Bruce D. 
Published: June 2014

ABSTRACTMeasurements of tibial plateau subchondral bone and articular cartilage slope have been associated with the risk of suffering anterior cruciate ligament (ACL) injury. Such single‐plane measures of the tibial plateau may not sufficiently characterize its complex, three‐dimensional geometry and how it relates to knee injury. Further, the tibial spines have not been studied in association with the risk of suffering a non‐contact ACL injury. We questioned whether the geometries of the tibial spines are associated with non‐contact ACL injury risk, and if this relationship is different for males and females. Bilateral MRI scans were acquired on 88 ACL‐injured subjects and 88 control subjects matched for sex, age and sports team. Medial and lateral tibial spine geometries were characterized with measurements of length, width, height, volume and anteroposterior location. Analyses of females revealed no associations between tibial spine geometry and risk of ACL injury. Analyses of males revealed that an increased medial tibial spine volume was associated with a decreased risk of ACL injury (OR = 0.667 per 100 mm3 increase). Smaller medial spines could provide less resistance to internal rotation and medial translation of the tibia relative to the femur, subsequently increasing ACL strains and risk of ACL injury. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1451–1457, 2014.
Determination of 15 sedative residues in mutton by rapid resolution liquid chromatography–tandem mass spectrometry
Authors: Wei Jinmei , Luo Yuzhu , Zhang Li , Fang Suli 
Published: June 2014

AbstractBACKGROUNDThe use of xenobiotic compounds in animal husbandry has given rise to consumer anxieties regarding residual risk and food safety. Thus, animal tissues have become main samples for residue analysis and food safety for sedatives. In this study, a rapid resolution liquid chromatography–tandem mass spectrometry (RRLC‐MS/MS) method was established for the determination of 15 sedatives residues in mutton.RESULTSAfter enzymolysis, sedatives residues in mutton were extracted by ammonium hydroxide–acetonitrile (10:90, v/v) and determined by RRLC‐MS/MS with quantification by standard curve method. The calibration curves showed good linearity within the concentrations of 0.5–50 µg kg−1 with the correlation coefficients (r2) ranged from 0.9639 to 0.9984. The limits of detection (LODs) and quantification (LOQs) were 0.25–2.5 and 0.5–5 µg kg−1, respectively. The average recoveries of spikes samples were in the ranges of 74.1–116.8% with relative standard deviations of intra‐ and inter‐day ranged from 2.6% to 11.2% and from 2.1% to 11.4%, respectively.CONCLUSIONThis method is simple, sensitive and accurate in the determination of sedative residues. © 2014 Society of Chemical Industry
Perineal reconstruction using pedicled vertical rectus abdominis myocutaneous flap (VRAM)
Authors: Touny Ahmed , Othman Haitham , Maamoon Sherif , Ramzy Samy , Elmarakby Hamdy 
Published: June 2014

BackgroundThe perineal wound is a major source of morbidity after abdominoperineal resection (APR) for rectal cancer, particularly after preoperative irradiation. Myocutaneous flap reconstruction is a viable alternative to primary perineal wound repair providing well‐vascularized non‐irradiated tissue to fill the dead space, and improve wound healing.Patients and MethodsSixty patients with low rectal cancer receiving neoadjuvant radiotherapy were prospectively randomized to either primary perineal wound closure (Group B) or VRAM perineal reconstruction (Group A). The study was carried out in the surgical department, National Cancer Institute (NCI), Cairo University over a period of 4 years from August 2008 to July 2012. All patients were evaluated as regards incidence of perineal wound complications, abdominal wall complications, and added co‐morbidity.ResultsPerineal wound complications were observed in 5 patients in group A (17.2%) and in 14 patients in group B (46.4%) (P = 0.015). There was no significant difference in the incidence of abdominal wound morbidity between both groups. Operative blood loss and time were lower in group B.ConclusionThe vertical rectus myocutaneous flap (VRAM) is a relatively simple and reliable technique for perineal wound reconstruction after abdominoperineal resection. J. Surg. Oncol. 2014 110:752–757. © 2014 Wiley Periodicals, Inc.
Determination of four sulfonylurea herbicides in tea by matrix solid‐phase dispersion cleanup followed by dispersive liquid–liquid microextraction
Authors: Liang Pei , Wang Jinjin , Liu Guojiao , Guan Jinyan 
Published: June 2014

Matrix solid‐phase dispersion combined with dispersive liquid–liquid microextraction has been developed as a new sample pretreatment method for the determination of four sulfonylurea herbicides (chlorsulfuron, bensulfuron‐methyl, chlorimuron‐ethyl, and pyrazosulfuron) in tea by high‐performance liquid chromatography with diode array detection. The extraction and cleanup by matrix solid‐phase dispersion was carried out by using CN‐silica as dispersant and carbon nanotubes as cleanup sorbent eluted with acidified dichloromethane. The eluent of matrix solid‐phase dispersion was evaporated and redissolved in 0.5 mL methanol, and used as the dispersive solvent of the following dispersive liquid–liquid microextraction procedure for further purification and enrichment of the target analytes before high‐performance liquid chromatography analysis. Under the optimum conditions, the method yielded a linear calibration curve in the concentration range from 5.0 to 10 000 ng/g for target analytes with a correlation coefficients (r2) ranging from 0.9959 to 0.9998. The limits of detection for the analytes were in the range of 1.31–2.81 ng/g. Recoveries of the four sulfonylurea herbicides at two fortification levels were between 72.8 and 110.6% with relative standard deviations lower than 6.95%. The method was successfully applied to the analysis of four sulfonylurea herbicides in several tea samples.