bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructural design of lead oxide–epoxy composites for radiation shielding purposes
Authors: Azman Nurul Zahirah Noor , Siddiqui Salim Ahmed , Hart Robin , Low It Meng 
Published: September 2012

AbstractComposite epoxy samples filled with PbO and Pb3O4 were fabricated to investigate the mass attenuation characteristics of the composites to X‐rays in the diagnostic imaging energy range. The effect of density on the attenuation ability of the composites for radiation shielding purposes was studied using a calibrated X‐ray machine. Characterization of the microstructure properties of the synthesized composites was performed using synchrotron radiation diffraction, optical microscopy, and scanning electron microscopy. The results indicate that the attenuation ability of the composites increased with an increase in density. The particle size of WO3 fillers has a negligible effect on the value of mass attenuation coefficient. Microstructural analyses have confirmed the existence of fairly uniform dispersion of fillers within the matrix of epoxy matrix with the average particle size of 1–5 μm for composites with filler loading of ≤ 30 wt % and 5–15 μm for composites with filler loading of ≥ 50 wt %. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
An Efficient Approach for the Construction of Benzazepine and Benzoxepine Derivatives
Authors: Li Shaoyu , Zou Shaowu , Wu Jie 
Published: September 2012

AbstractA novel and facile synthetic protocol for the construction of benzazepine and benzoxepine derivatives through a copper(I)‐catalyzed reaction of 2‐(2‐ethynylphenyl)‐1‐tosylaziridine or 2‐(2‐ethynylphenyl)oxirane with sulfonyl azides is disclosed. A ketenimine is the key intermediate during the reaction process.
The Unprecedented Tetrakis‐(disulfato)‐silicate Anion [Si(S2O7)4]4−, its Germanium Congener [Ge(S2O7)4]4−, and the Tris‐(disulfato)‐metallates [M(S2O7)3]2− (M=Si, Ge, Ti), Stabilized by Divalent Counter Cations B2+ (B=Sr, Ba, Pb)
Authors: Logemann Christian , Rieß Katja , Wickleder Mathias S. 
Published: September 2012

AbstractThe reaction of oleum (65 % SO3) with the tetrachlorides of silicon, germanium, and titanium, respectively, led to the complex disulfates Sr2[M(S2O7)4] (M=Si, Ge), Ba[M(S2O7)3] (M=Si, Ge, Ti) and Pb[M(S2O7)3] (M=Ge, Ti) if strontium, barium, and lead were used as divalent counter cations. The strontium compounds exhibit the unique tetrakis‐(disulfato)‐metallate anions [M(S2O7)4]4− with the silicon and germanium atoms in octahedral coordination of two chelating and two monodentate disulfate groups. All of the other compounds display tris‐(disulfato)‐metallate anions [M(S2O7)3]2− with three chelating disulfate groups surrounding the M atoms. Thermoanalytical investigations on the germanium compounds Sr2[Ge(S2O7)4] and Ba[Ge(S2O7)3] revealed their decomposition in multi‐step processes leading to a mixture of BSO4 and BGe4O9 (B=Sr, Ba), while the thermal degradation of Pb[Ti(S2O7)3] yields PbTiO3. For selected examples, IR data are additionally presented.
Adaptive Control of Piecewise Linear Systems with State Feedback for Output Tracking
Authors: Sang Qian , Tao Gang 
Published: September 2012

AbstractA piecewise linear system consists of a set of linear time‐invariant (LTI) subsystems, with a switching sequence specifying an active subsystem at each time instant. This paper studies the adaptive control problem of single‐input, single‐output (SISO) piecewise linear systems. By employing the knowledge of the time instant indicator functions of system parameter switches, a new controller structure parametrization is proposed for the development of a stable adaptive control scheme with reduced modeling error in the estimation error signal used for parameter adaptive laws. This key feature is achieved by the new control scheme's ability to avoid a major parameter swapping term in the error model, with the help of indicator functions whose knowledge is available in many applications. A direct state feedback model reference adaptive control (MRAC) scheme is presented for such systems to achieve closed‐loop signal boundedness and small output tracking error in the mean square sense, under the usual slow system parameter switching condition. Simulation results on linearized NASA GTM models are presented to demonstrate the effectiveness of the proposed scheme.
Selection and in vitro characterization of human CD44v6‐binding antibody fragments
Authors: Nilvebrant Johan , Kuku Gamze , Björkelund Hanna , Nestor Marika 
Published: September 2012

AbstractThe cluster of differentiation (CD) 44v6 antigen has been suggested to be involved in tumor formation, invasion, and metastasis formation, and has been observed in a majority of primary and metastatic squamous cell carcinomas of the head and neck. Probes specifically binding to this region may be utilized as tools for the challenging tasks of early detection and targeted treatments of small residual disease. In this project, an epitope‐guided phage display selection of human fragment antigen‐binding (Fab) fragments with affinity to the v6 sequence was performed. A selected set of Fab fragments was shown to specifically recognize increasingly complex forms of the target sequence, both in the form of a short synthetic or recombinant peptide and in the context of a purified extracellular domain of CD44. The binding was independent of known v6‐sequence variation and posttranslational modifications that are common in the CD44 protein family. Furthermore, real‐time interaction measurements on antibody fragments labeled with 125I showed specific and high‐affinity binding to the antigen present on cultured head and neck squamous cell carcinoma cells. There was no cross‐reactivity toward cells that lack the target protein. As hypothesized, characterization of the interaction between Fab fragments and the targets using the mathematical tool Interaction Map revealed more heterogeneous interactions on cells than with pure proteins analyzed by surface plasmon resonance. One main candidate Fab fragment with optimal affinity for all forms of the target sequence was identified. The flexible recombinant source of the Fab fragments might aid the development of tailored molecules adapted for therapeutic or diagnostic applications in the future.
Molecular mechanisms of curcumin action: Gene expression
Authors: Shishodia Shishir 
Published: September 2012

AbstractCurcumin derived from the tropical plant Curcuma longa has a long history of use as a dietary agent, food preservative, and in traditional Asian medicine. It has been used for centuries to treat biliary disorders, anorexia, cough, diabetic wounds, hepatic disorders, rheumatism, and sinusitis. The preventive and therapeutic properties of curcumin are associated with its antioxidant, anti‐inflammatory, and anticancer properties. Extensive research over several decades has attempted to identify the molecular mechanisms of curcumin action. Curcumin modulates numerous molecular targets by altering their gene expression, signaling pathways, or through direct interaction. Curcumin regulates the expression of inflammatory cytokines (e.g., TNF, IL‐1), growth factors (e.g., VEGF, EGF, FGF), growth factor receptors (e.g., EGFR, HER‐2, AR), enzymes (e.g., COX‐2, LOX, MMP9, MAPK, mTOR, Akt), adhesion molecules (e.g., ELAM‐1, ICAM‐1, VCAM‐1), apoptosis related proteins (e.g., Bcl‐2, caspases, DR, Fas), and cell cycle proteins (e.g., cyclin D1). Curcumin modulates the activity of several transcription factors (e.g., NF‐κB, AP‐1, STAT) and their signaling pathways. Based on its ability to affect multiple targets, curcumin has the potential for the prevention and treatment of various diseases including cancers, arthritis, allergies, atherosclerosis, aging, neurodegenerative disease, hepatic disorders, obesity, diabetes, psoriasis, and autoimmune diseases. This review summarizes the molecular mechanisms of modulation of gene expression by curcumin. © 2012 BioFactors, 39(1):37–55, 2013.
Applied and Workforce Baccalaureate Models
Authors: Floyd Deborah L. , Garcia Falconetti Angela M. , Felsher Rivka A. 
Published: September 2012

AbstractThis chapter presents models and terminology representative of the contemporary utilization of the terms community college baccalaureate, applied baccalaureate, and workforce baccalaureate to provide a foundation for the evolving language about pathways leading to baccalaureate degrees.
Effects of Axle‐Core, Macrocycle, and Side‐Station Structures on the Threading and Hydrolysis Processes of Imine‐Bridged Rotaxanes
Authors: Sugino Hiroyoshi , Kawai Hidetoshi , Umehara Takeshi , Fujiwara Kenshu , Suzuki Takanori 
Published: September 2012

AbstractImine‐bridged rotaxanes are a new type of rotaxane in which the axle and macrocyclic ring are connected by imine bonds. We have previously reported that in imine‐bridged rotaxane 5, the shuttling motion of the macrocycle could be controlled by changing the temperature. In this study, we investigated how the axle and macrocycle structures affect the construction of the imine‐bridged rotaxane as well as the dynamic equilibrium between imine‐bridged rotaxane 5 and [2]rotaxane 7 by using various combinations of axles (1 A,B), macrocycles (2 a–e), and side‐stations (XYL and TEG). In the threading process, the flexibility of the macrocycle and the substituent groups at the para position of the aniline moieties affect the preparation of the threaded imines. The size of the imine‐bridging station and the macrocyclic tether affects the hydrolysis of the imine bonds under acidic conditions.
Radical Localization in a Series of Symmetric NiIIComplexes with Oxidized Salen Ligands
Authors: Chiang Linus , Kochem Amélie , Jarjayes Olivier , Dunn Tim J. , Vezin Hervé , Sakaguchi Miyuki , Ogura Takashi , Orio Maylis , Shimazaki Yuichi , Thomas Fabrice , Storr Tim 
Published: September 2012

AbstractSquare‐planar nickel(II) complexes of salen ligands,N,N′‐bis(3‐tert‐butyl‐(5R)‐salicylidene)‐1,2‐cyclohexanediamine), in which R=tert‐butyl (1), OMe (2), and NMe2(3), were prepared and the electronic structure of the one‐electron‐oxidized species [1–3]+.was investigated in solution. Cyclic voltammograms of [1–3] showed two quasi‐reversible redox waves that were assigned to the oxidation of the phenolate moieties to phenoxyl radicals. From the difference between the first and second redox potentials, the trend of electronic delocalization1+.>2+.>3+.was obtained. The cations [1–3]+.exhibited isotropicgtensors of 2.045, 2.023, and 2.005, respectively, reflecting a lower metal character of the singly occupied molecular orbital (SOMO) for systems that involve strongly electron‐donating substituents. Pulsed‐EPR spectroscopy showed a single population of equivalent imino nitrogen atoms for1+., whereas two distinct populations were observed for2+.. The resonance Raman spectra of2+.and3+.displayed the ν8aband of the phenoxyl radicals at 1612 cm−1, as well as theν8abands of the phenolates. In contrast, the Raman spectrum of1+.exhibited theν8aband at 1602 cm−1, without any evidence of the phenolate peak. Previous work showed an intense near‐infrared (NIR) electronic transition for1+.(Δν1/2=660 cm−1,ε=21 700 M−1 cm−1), indicating that the electron hole is fully delocalized over the ligand. The broader and moderately intense NIR transition of2+.(Δν1/2=1250 cm−1,ε=12 800 M−1 cm−1) suggests a certain degree of ligand‐radical localization, whereas the very broad NIR transition of3+.(Δν1/2=8630 cm−1,ε=2550 M−1 cm−1) indicates significant localization of the ligand radical on a single ring. Therefore,1+.is a Class III mixed‐valence complex,2+.is Class II/III borderline complex, and3+.is a Class II complex according to the Robin–Day classification method. By employing the Coulomb‐attenuated method (CAM‐B3LYP) we were able to predict the electron‐hole localization and NIR transitions in the series, and show that the energy match between the redox‐active ligand and the metal d orbitals is crucial for delocalization of the radical SOMO.
Synthesis and Self‐Association of Double‐Helical AADD Arrays
Authors: Mudraboyina Bhanu P. , Wisner James A. 
Published: September 2012

AbstractThe design and syntheses of four self‐complementary oligomers that contain an underlying AADD hydrogen bond sequence are presented, and their self‐association was examined in the solution and solid state. The molecular recognition between the two strands is highly sensitive to substitutions of their component heterocycles. Substitution with electron‐donating and ‐withdrawing groups and the influence of preorganization has a large effect on the overall stabilities of the complexes studied. In particular, a wide range (>105 M−1) of stabilities with respect to substitutions at various positions in the AADD oligomers was demonstrated. In the most extreme case, the dimerization constant measured (Kdimer≥4.5×107 M−1) is comparable to the most stable homodimers of neutral AADD arrays reported to date.
Highly Selective Barbier‐Type Propargylations and Allenylations Catalyzed by Titanocene(III)
Authors: Muñoz‐Bascón Juan , Sancho‐Sanz Iris , Álvarez‐Manzaneda Enrique , Rosales Antonio , Oltra J. Enrique 
Published: September 2012

AbstractThe alkyne functional group is found in many bioactive natural products and is the key to many important chemical transformations developed over recent years. Moreover, allenes have recently gained relevance as versatile reagents in organic synthesis. Mild, catalytic methods to enable the selective introduction of either alkyne or allene motifs into organic molecules are very valuable but, as yet, quite scarce. We describe an extremely mild and selective method for either the propargylation or allenylation of carbonyl compounds catalyzed by the abundant, safe, and inexpensive metal titanium. These reactions can selectively provide homopropargylic alcohols from aldehydes and ketones or α‐hydroxy‐allenes from aldehydes. The mechanisms involved were also investigated.
Coupling of Two Multistep Catalytic Cycles for the One‐Pot Synthesis of Propargylamines from Alcohols and Primary Amines on a Nanoparticulated Gold Catalyst
Authors: Corma Avelino , Navas Javier , Sabater María J. 
Published: September 2012

AbstractA one‐pot reaction was performed with a nanoparticulated gold catalyst. A secondary amine is formed through N‐monoalkylation of a primary amine with an alcohol by a borrowing hydrogen methodology in a three‐step reaction. The secondary amine formed enters into a second A3‐coupling cycle to give propargylamines. The multistep reaction requires a gold species formed and stabilized on a ceria surface.
Structural Changes in a Protein Fragment from Abalone Shell during the Precipitation of Calcium Carbonate
Authors: Adamiano Alessio , Bonacchi Sara , Calonghi Natalia , Fabbri Daniele , Falini Giuseppe , Fermani Simona , Genovese Damiano , Kralj Damir , Montalti Marco , Njegić Džakula Branka , Prodi Luca , Sartor Giorgio 
Published: September 2012

AbstractMineralized tissues grow through biologically controlled processes in which specific macromolecules are involved. Some of these molecules, which are present in very low concentrations and are difficult to localize and characterize, become entrapped inside the mineralized tissue. Herein, a protein fragment, GP, which was obtained by the alkaline digestion of the green sheet of the abalone shell, is used as a probe to study the changes in molecular structure that occur during the precipitation of calcium carbonate. This important goal was achieved by exploiting a fluorescent tag in GP. The experimental results that were obtained by using spectroscopic‐, chromatographic‐, and microscopic techniques indicate that GP controls the precipitation kinetics and morphology of calcium carbonate crystals, and that it only undergoes structural reorganization when entrapped inside calcium carbonate crystals. To the best of our knowledge, this report represents one of the first studies on the conformational changes of a protein fragment that is involved in biomineralization processes on moving from the solution phase into the mineral phase.
Ultrafast Photoinduced Energy and Electron Transfer in Multi‐Modular Donor–Acceptor Conjugates
Authors: El‐Khouly Mohamed E. , Wijesinghe Channa A. , Nesterov Vladimir N. , Zandler Melvin E. , Fukuzumi Shunichi , D'Souza Francis 
Published: September 2012

AbstractNew multi‐modular donor–acceptor conjugates featuring zinc porphyrin (ZnP), catechol‐chelated boron dipyrrin (BDP), triphenylamine (TPA) and fullerene (C60), or naphthalenediimide (NDI) have been newly designed and synthesized as photosynthetic antenna and reaction‐center mimics. The X‐ray structure of triphenylamine‐BDP is also reported. The wide‐band capturing polyad revealed ultrafast energy‐transfer (kENT=1.0×1012 s−1) from the singlet excited BDP to the covalently linked ZnP owing to close proximity and favorable orientation of the entities. Introducing either fullerene or naphthalenediimide electron acceptors to the TPA‐BDP‐ZnP triad through metal–ligand axial coordination resulted in electron donor–acceptor polyads whose structures were revealed by spectroscopic, electrochemical and computational studies. Excitation of the electron donor, zinc porphyrin resulted in rapid electron‐transfer to coordinated fullerene or naphthalenediimide yielding charge separated ion‐pair species. The measured electron transfer rate constants from femtosecond transient spectral technique in non‐polar toluene were in the range of 5.0×109–3.5×1010 s−1. Stabilization of the charge‐separated state in these multi‐modular donor–acceptor polyads is also observed to certain level.
ChemInform Abstract: The Significance of Ionic Bonding in Sulfur Dioxide: Bond Orders from X‐Ray Diffraction Data.
Authors: Grabowsky Simon , Luger Peter , Buschmann Juergen , Schneider Thomas , Schirmeister Tanja , Sobolev Alexandre N. , Jayatilaka Dylan 
Published: September 2012

AbstractInformation on the S—O bond‐order in crystalline SO2 is derived from wavefunction refinement of high‐resolution low‐temperature XRD data.
ChemInform Abstract: Pentaguanidinium Monohydrogendiphosphogentamolybdate(VI) 2.5‐Hydrate, (CH6N3)5 [HP2Mo5O23]·2.5H2O: Hydrogen Bonding and π‐Stacking in Guanidinium Cations.
Authors: Di Tondo Pietro , Pritchard Robin Gavin 
Published: September 2012

AbstractColorless needles of the title compound are obtained by evaporation of an aqueous solution of guanidinium carbonate and H3[P(Mo3O10)4] over a period of 5 d.
ChemInform Abstract: Role of Oxidative Pre‐Calcination in Extending Blue Emission of Sr4Al14O25 Nanophosphors Formed with Microemulsions.
Authors: Thompson Nathan , Murugaraj Pandiyan , Rix Colin , Mainwaring David E. 
Published: September 2012

AbstractSingle phase blue emitting long persistence Sr4‐x‐yEuxDyyAl14O25 (0.005 ≤ x ≤ 0.04; 0.01 ≤ y ≤ 0.01) nanophosphors are synthesized in the presence of 5 mol% boric acid at 1100 °C in a reducing atmosphere for 3 h from precursor particles which are formed within microemulsions and pre‐calcined at 1000 °C in ambient atmosphere for 2 h.
ChemInform Abstract: Synthesis and Electrochemical Properties of Li3V2(PO4)3/C with One‐Dimensional (1D) Nanorod Structure for Cathode Materials of Lithium‐ion Batteries.
Authors: Shen Yuhua , et al. et al. 
Published: September 2012

AbstractThe title cathode material is synthesized by a sol—gel method using maleic acid as a carbon source.
ChemInform Abstract: Hierarchical Nanostructures of Fluorinated and Naked Ta2O5 Single Crystalline Nanorods: Hydrothermal Preparation, Formation Mechanism and Photocatalytic Activity for H2 Production.
Authors: Duan Junyuan , Shi Weidong , Xu Leilei , Mou Guangying , Xin Quanliang , Guan Jianguo 
Published: September 2012

AbstractFluorinated Ta2O5 nanostructures are synthesized by hydrothermal reaction of Ta powder, 0.133 M aq.
ChemInform Abstract: Synthesis of ZrB2 Powders by Carbothermal and Borothermal Reduction.
Authors: Jung Eun‐Young , Kim Jung‐Hun , Jung Se‐Hyuk , Choi Sung‐Churl 
Published: September 2012

AbstractThe synthesis methods of ZrB2 powders using ZrO2 + B2O3 + C (carbothermal reduction), ZrO2 + B4C (boron carbide reduction), and ZrO2 + B4C + C (combined reduction) at 1250 °C for 1—3 h under flowing Ar are compared.
ChemInform Abstract: A Germanate Compound Constructed from Dissymmetric Ge7 Chains and Metal Complexes.
Authors: Ren Xiaoyan , Li Yi , Shao Lang , Yu Jihong , Xu Ruren 
Published: September 2012

AbstractThe new compound {[Ni(dien)2]3(H2O)3} [Ge7O13F5]2 (dien: diethylenetriamine) is solvothermally synthesized from a mixture of GeO2, Ni(NO3)2, 3‐amino‐1‐propanol, dien, H2O, and HF in a molar ratio of 1.0:0.5:65.4:18.6:63.2:2.7 (autoclave, 180 °C, 8 d).
ChemInform Abstract: Synthesis, Crystal Structure and Properties of Li2Cu5(PO4)4.
Authors: Snyder Katharina , Glaum Robert 
Published: September 2012

AbstractPolycrystalline Li2Cu5(PO4)4 is prepared by slow evaporation of a solution of Li2CO3, Cu, and (NH4)2HPO4 in 65% aq.
ChemInform Abstract: cis‐1,4‐Bis(triphenylphosphonium)‐2‐butene Peroxodisulfate as an Efficient Reagent for the Synthesis of Phenacyl Thiocyanates and Phenacyl Azides.
Authors: Badri Rashid , Gorjizadeh Maryam 
Published: September 2012

AbstractThe thiocyanation and azidation of styrenes in the presence of 1,4‐bis(triphenylphosphonium)‐2‐butene peroxodisulfate proceeds under mild conditions with good yields.
ChemInform Abstract: Organocatalytic 1,4‐Addition Reaction of α,.beta±gamma.,δ‐Diunsaturated Aldehydes versus 1,6‐Addition Reaction.
Authors: Hayashi Yujiro , Okamura Daichi , Umemiya Shigenobu , Uchimaru Tadafumi 
Published: September 2012

AbstractThe conjugate addition of nitromethane (II), cyclopentadiene (IV) or nitroethanol (VIII) towards α,β,γ,δ‐unsaturated aldehydes in the presence of a prolinol‐derived organocatalyst proceeds chemoselectively in a 1,4‐addition mode.
ChemInform Abstract: Synthesis of Thiazine and Thiazepine Derivatives from (Z)‐2‐Cyano‐3‐mercapto‐3‐(phenylamino)acrylamide.
Authors: El‐Shaieb Kamal M. , Abdel‐Latif Fathy F. , El‐Din Ahmed G. 
Published: September 2012

AbstractDepending on the substrate used the reaction with the title amide (II) leads to thiazine or thiazepine derivatives.
ChemInform Abstract: Substrate‐Dependent Divergent Outcomes from Catalytic Reactions of Silyl‐Protected Enol Diazoacetates with Nitrile Oxides: Azabicyclo[3.1.0]hexanes or 5‐Arylaminofuran‐2(3H)‐ones.
Authors: Xu Xinfang , Shabashov Dmitry , Zavalij Peter Y. , Doyle Michael P. 
Published: September 2012

AbstractThe reaction is found to result in formation of azabicyclohexanes and/or arylaminofurans depending on the electronic nature of the aryl substituents.
ChemInform Abstract: Rhodium‐Catalyzed Dynamic Kinetic Asymmetric Transformations of Racemic Tertiary Allylic Trichloroacetimidates with Anilines.
Authors: Arnold Jeffrey S. , Nguyen Hien M. 
Published: September 2012

AbstractThe first dynamic kinetic asymmetric transformation of racemic tertiary allylic acetimidates with aniline nucleophiles using a rhodium—diene ligand complex is described to give the branched amines (III) or (VI) with regioselectivities between <99:1 and 5:1 compared to their linear analogues.
ChemInform Abstract: Palladium‐Catalyzed C—H Bond Direct Alkynylation of 5‐Membered Heteroarenes: A Well‐Defined Synthetic Route to Azole Derivatives Containing Two Different Alkynyl Groups.
Authors: Shibahara Fumitoshi , Dohke Yoshimasa , Murai Toshiaki 
Published: September 2012

AbstractThe Pd/Ag‐mediated dropwise addition of terminal alkynes to various 5‐membered azoles allows an easy access to a number of mono‐ and dialkynylated heteroarenes.
ChemInform Abstract: Solvent‐Free Esterification of Carboxylic Acids and Alcohols in the Presence of Silphos [PCl3‐n(SiO2)n] as a Heterogeneous Phosphine Reagent.
Authors: Rao Ambati Narasimha , Ganesan Kumaran , Shinde Chandra Kant 
Published: September 2012

AbstractSilphos is shown to be an efficient catalyst for the solvent‐free esterification of aromatic and aliphatic carboxylic acids and a wide range of primary, secondary and tertiary alcohols at room temperature.