bluuebunny/crossref_metadata_2025_split huggingface dataset:
Group 4 complexes bearing alkoxide functionalized N‐heterocyclic carbene ligands as catalysts in the polymerization of olefins
Authors: Costabile Chiara , Bocchino Carmen , Napoli Mariagrazia , Longo Pasquale 
Published: June 2012

AbstractNovel octahedral zirconium complexes bearing alkoxide functionalized N‐heterocyclic carbene ligands have been synthesized and characterized. NMR analysis showed that more than one species was obtained during synthesis. The synthesized complexes were able to polymerize ethylene and propylene giving rise to a linear polyethylene with high Mw and polydispersity index often bimodal with molecular weight distribution (MDI) > 2, and highly isotactic polypropylene together with an atactic fraction. Density functional theory (DFT) studies on the complex stability indicate the possible species active during the polymerization reaction. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Factors reported to influence fear of recurrence in cancer patients: a systematic review
Authors: Crist Jade V. , Grunfeld Elizabeth A. 
Published: June 2012

AbstractObjectiveFear of cancer recurrence (FCR) is a significant psychological problem for cancer survivors. Some survivors experience FCR, which is both persistent and highly distressing. The aim of this systematic review was to identify the key factors associated with fear of recurrence among cancer patients.MethodsA comprehensive literature search using keywords was performed with three databases, followed by an organic search to identify additional relevant articles. Included studies had a quantitative methodology presenting empirical findings focussed on adult cancer patients. A methodological quality assessment was performed for each study, and the strength of evidence was defined by the consistency of results.ResultsForty‐three studies met the inclusion criteria and are presented in this review. The most consistent predictor of elevated FCR was younger age. There was strong evidence for an association between physical symptoms and fear of cancer recurrence. Additional factors moderately associated with increased FCR included treatment type, low optimism, family stressors and fewer significant others. Inconsistent evidence was found for socio‐demographic factors.ConclusionsFear of cancer recurrence is a complex issue influenced by a multitude of factors, including demographic, clinical and psychological factors. However, some studies have reported contradictory evidence, and FCR has been measured using a range of scales, which can hamper comparison across studies. Further research is needed to clarify inconsistencies in the current published research. Copyright © 2012 John Wiley & Sons, Ltd.
Characterization of 4,6‐Diazido‐N‐nitro‐1,3,5‐triazine‐2‐amine
Authors: Musil Tomáš , Matyáš Robert , Lyčka Antonín , Růžička Aleš 
Published: June 2012

Abstract4,6‐Diazido‐N‐nitro‐1,3,5‐triazine‐2‐amine (DANT) was prepared with a 35 % yield from cyanuric chloride in a three step process. DANT was characterized by IR and NMR spectroscopy (1H, 13C, 15N), single‐crystal X‐ray diffraction, and DTA. The crystal density of DANT is 1.849 g cm−3. The cyclization of one azido group and one nitrogen atom of the triazine group giving tetrazole was observed for DANT in a dimethyl sulfoxide solution using NMR spectroscopy. An equilibrium exists between the original DANT molecule and its cyclic form at a ratio of 7 : 3. The sensitivity of DANT to impact is between that for PETN and RDX, sensitivity to friction is between that for lead azide and PETN, and sensitivity to electric discharge is about the same as for PETN. DANT′s heat of combustion is 2060 kJ mol−1.
Explosive Strength and Impact Sensitivity of Several PBXs Based on Attractive Cyclic Nitramines
Authors: Elbeih Ahmed , Jungová Marcela , Zeman Svatopluk , Vávra Pavel , Akštein Zbyněk 
Published: June 2012

AbstractPlastic explosives based on different cyclic nitramines with different polymeric matrices were prepared and studied. The used polymeric matrices were fabricated on the basis of polyisobutylene (PIB), acrylonitrile‐butadiene rubber (ABR), Viton A, and polydimethyl‐siloxane as binders, whereas the nitramines named RDX (1,3,5‐trinitroperhydro‐1,3,5‐triazine), β‐HMX (β‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine), BCHMX (cis‐1,3,4,6‐tetranitrooctahydroimidazo‐[4,5‐d]imidazole) and ε‐HNIW (ε‐2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane) were used as explosive fillers. Commercial Semtex 10, based on pentaerythritol tetranitrate (PETN), was used for comparison. Impact sensitivity, loading density, ρ, detonation velocity, D, and relative explosive strength (RS) measured by ballistic mortar were determined. It was concluded that plastic BCHMX based on Viton A or PIB‐matrix exhibits higher RS compared with PBXs based on RDX and HMX. Correlations between RS and the impact sensitivity, the ρD2 term and the square of the detonation velocity were studied and discussed. The results confirm the well‐known fact that increasing the performance is usually accompanied by an increase in the sensitivity of the explosives. In this connection, Viton A enables achieving a high RS, but with a relatively high sensitivity of the PBXs, whereas the polydimethyl‐siloxane matrix should perhaps give PBXs with optimum explosive strength and sensitivity parameters.
Predicting Maximum Attainable Detonation Velocity of CHNOF and Aluminized Explosives
Authors: Keshavarz Mohammad Hossein 
Published: June 2012

AbstractThis paper describes a simple method to predict the detonation velocity of pure and mixed CHNOF explosives as well as aluminized explosives at their maximum nominal density as one of the most important detonation properties. The new correlation uses the contribution of some structural parameters to apply for a wide range of ideal and non‐ideal explosives. Aluminized explosives have non‐ideal behavior and the ChapmanJouguet detonation velocities significantly differ from those expected from existing thermodynamic computer codes for equilibrium and steady state calculations. With the presented method, there is no need to use any assumed detonation products, heat of formation and experimental data. Detonation velocities at maximum nominal density of explosives predicted by this procedure show good agreement with respect to experimental values. They are more reliable compared to the calculated results of well‐known empirical methods and computed outputs using BKWS equation of state for CHNOF and aluminized explosives.
Aminonitrocyclopropanes as Possible High‐Energy Materials. Quantum Chemical Calculations
Authors: Halstead Joshua M. , Whittaker Jessica N. , Ball David W. 
Published: June 2012

AbstractThe structures, vibrational spectra, and thermodynamic properties of three cyclopropane derivatives with amino and nitro substitutions were evaluated using standard density functional calculations. Calculations of thermodynamic properties show that the energy content per unit mass of these compounds is higher than current high energy materials. The actual density of these substances may be higher than that calculated because of expected intermolecular interactions between adjacent NH2 and NO2 groups.
Role of aluminium oxide in the structure of heavy metal oxide borosilicate glasses
Authors: Monika  , Falconieri M. , Baccaro S. , Sharma G. , Thind K. S. , Singh D. P. 
Published: June 2012

AbstractLead borosilicate and bismuth borosilicate glasses with and without aluminium oxide of varying compositions were prepared by conventional melt‐quench method. Raman spectroscopy was used to analyze the influence of Al2O3 incorporation in the heavy metal oxide borosilicate glass network. The compositions of glasses were chosen in a way that Al2O3 is added at expenses of PbO and Bi2O3 in lead borosilicate and bismuth borosilicate glasses, respectively.
Energy harvesting using multilayer structure based on La‐doped PMN‐PT electrostrictive ceramics
Authors: Huang Hualin , Li Guorong , Huang Lizhu , Ruan Wei , Cheng Lihong , Zeng Jiangtao , Wen Baosong 
Published: June 2012

AbstractElectrostrictive materials exhibit high induced strain under dc electric fields and this effect is important in generator application. This paper studied the energy‐harvesting performances of La‐doped PMN‐PT electrostrictive ceramics that have rarely been reported. A multilayer structured electrostrictive energy harvester with high dielectric constant and electrostrictive coefficient is proposed. With a strain Sm = 7 × 10−5 (m/m), a peak current value of 630 µA is obtained across a small matched resistance of 450 Ω under a dc electrical field of 1.5 V/µm. The working principle of the device is reviewed and improved to predict the current and power generated by the harvester. Experimental results are compared to the theoretic behaviors of the improved model. A good agreement is observed by the two sets of data. The study on the efficiency of the energy conversion showed that a positive balance between the consumed power and the harvested power was presented by the device. The result demonstrates the potential perspective of the electrostrictive device in energy harvesting applied to low‐power electronics.
Sulfurization of near‐stoichiometric CuIn precursor and the influence of low‐temperature slopes on morphology and structural quality
Authors: Dombrowa A. , Lehmann C. , Pettenkofer C. 
Published: June 2012

AbstractPolycrystalline CuInS2 (CIS) films are prepared by sulfurization of CuIn metallic precursors with Cu/In = 1.2 on Mo substrates. Variation of the rapid thermal processing (RTP) parameters adjusted to the low copper surplus yielded near stoichiometric CIS films with considerably less CuSx precipitation at the surface. A start temperature and low temperature slopes were introduced to guarantee crystal quality and large grain size. XPS/UPS, X‐ray diffraction measurement, and scanning electron microscopy data show the distinct properties of the chalcopyrite phase and its morphological structure in comparison to the standard sulfurization process. A considerable improvement has been achieved by variation of the temperature profiles. The proposed process modules obtain near stoichiometric CIS films for industrial solar cell production.
Many electrons on a mesoscopic cylinder in a threading magnetic field: Persistent current and magnetization
Authors: Onorato P. 
Published: June 2012

AbstractThe behavior of Ne interacting electrons confined in a mesoscopic “quantum” cylinder, QC, threaded by an Aharonov–Bohm (AB) flux ϕ is carefully analyzed by using a Hartree–Fock approximation. The ground state energies of the QC as a function of the magnetic field, B, and the electron–electron repulsion strength, U, are obtained. A phase diagram is presented indicating a rich variety of ground states and the spin and orbital magnetization responses to the magnetic field's variations are discussed. The behavior of persistent current is investigated and a significant change in current amplitude is observed when the strength of the electron–electron repulsion increases.
Stability and bonding in the borane–H2complexes
Authors: Méndez Mariano , Cedillo Andrés 
Published: June 2012

AbstractThe ability of substituted boranes, XnBH3−n, to form stable complexes with the hydrogen molecule is analyzed by making use of computational chemistry and local reactivity parameters. In these complexes, the hydrogen molecule acts as a Lewis base while the borane moiety is the Lewis acid. Electronegative groups (X = CF3, F, OH) are selected to increase the acidity of the borane and it is found that the energetic stability of the complexes is only increased for the trifluoromethyl‐substituted Lewis acids, at the MP2/6‐311++g(3df, 3pd) level. It is also found that the BLYP density functional underestimates the adduct stability of these species. On the other hand, fluoroboranes and hydroxyboranes do not form donor–acceptor adducts with the hydrogen molecule; instead, we find weakly bounded van der Waals complexes. Additional features on the intrinsic reactivity of boranes are analyzed with the molecular electrostatic potential and the acceptor Fukui function. The nature of the interaction among the boranes and the hydrogen molecule is explored by using the topological analysis of the electron density through the Bader's Atoms‐in‐Molecules theory. © 2012 Wiley Periodicals, Inc.
Finite‐time formation control of multiagent systems via dynamic output feedback
Authors: Du Haibo , Li Shihua , Lin Xiangze 
Published: June 2012

SUMMARYFinite‐time formation control of multiple second‐order agents via dynamic output feedback is investigated in this paper. Under the assumption that the velocities of all agents cannot be measured, a continuous consensus algorithm is first proposed such that the states of all agents will reach an agreement in finite time. Then, the consensus algorithm is applied to the finite‐time formation control, including stationary formation and moving formation, respectively. Rigorous proof shows that all agents will converge to the desired formation pattern in finite time. Finally, an example is given to verify the efficiency of the proposed method. Copyright © 2012 John Wiley & Sons, Ltd.
State‐saturatedH∞filtering with randomly occurring nonlinearities and packet dropouts: the finite‐horizon case
Authors: Ding Derui , Wang Zidong , Shen Bo , Shu Huisheng 
Published: June 2012

SUMMARYThis paper deals with theH∞filtering problem for a class of discrete time‐varying systems with state saturations, randomly occurring nonlinearities as well as successive packet dropouts. Two mutually independent sequences of random variables that obey the Bernoulli distribution are employed to describe the random occurrence of the nonlinearities and packet dropouts. The purpose of the addressed problem is to design a time‐varying filter such that theH∞disturbance attenuation level is guaranteed, over a given finite‐horizon, for the filtering error dynamics in the presence of saturated states, randomly occurring nonlinearities, and successive packet dropouts. By introducing a free matrix with its infinity norm less than or equal to 1, the error state is bounded by a convex hull so that some sufficient conditions obtained via solving a certain set of recursive nonlinear matrix inequalities. Furthermore, the obtained results are extended to the case when state saturations are partial. Two numerical simulation examples are provided to demonstrate the effectiveness and applicability of the proposed filter design approach. Copyright © 2012 John Wiley & Sons, Ltd.
How is Flow Experienced and by Whom? Testing Flow among Occupations
Authors: Llorens Susana , Salanova Marisa , Rodríguez Alma Mª 
Published: June 2012

AbstractThe aims of this paper are to test (1) the factorial structure of the frequency of flow experience at work; (2) the flow analysis model in work settings by differentiating the frequency of flow and the frequency of its prerequisites; and (3) whether there are significant differences in the frequency of flow experience depending on the occupation. A retrospective study among 957 employees (474 tile workers and 483 secondary school teachers) using multigroup confirmatory factorial analyses and multiple analyses of variance suggested that on the basis of the flow analysis model in work settings, (1) the frequency of flow experience has a two‐factor structure (enjoyment and absorption); (2) the frequency of flow experience at work is produced when both challenge and skills are high and balanced; and (3) secondary school teachers experience flow more frequently than tile workers. Copyright © 2012 John Wiley & Sons, Ltd.
Small‐Sized Carbon Nanohorns Enabling Cellular Uptake Control
Authors: Zhang Minfang , Zhou Xin , Iijima Sumio , Yudasaka Masako 
Published: June 2012

AbstractCarbon nanotubes perform well in preclinical tests for drug delivery and diagnostic imaging, but controlling the size at less than 100 nm to avoid nonspecific uptake by reticuloendothelial systems while targeting delivery to cells of interest via receptor‐mediated endocytosis is difficult, which currently limits their widespread use. Herein, 20–50‐nm graphene tubules, small‐sized single‐walled carbon nanohorns (S‐SWNHs), are obtained with a yield of 20% or higher by an oxidative exfoliation of 100 nm pristine SWNH aggregates. S‐SWNHs are highly hydrophilic and remarkably resistant to cellular uptake by macrophages (RAW 264.7 cells), tumor cells (HeLa or KB), or normal cells (FHs 173We). The nonstimulatory property to cell membranes therefore makes cellular uptake control of S‐SWNHs by functionalization easy. By attaching phospholipid polyethylene glycol, the cellular internalization of S‐SWNHs is almost completely inhibited in RAW 264.7 macrophages. When functionalized with tumor‐targeting folic acid (FA), FA‐S‐SWNHs are taken up by FA receptor‐overexpressing KB cells but not by normal human embryonic cells (FHs 173We), which do not express the FA receptor. With a high rate of stealth and targeting in vitro, S‐SWNHs are one of the most promising nanoparticles for medical use.
Patterning of Crystalline Organic Materials by Electro‐hydrodynamic Lithography
Authors: Goldberg‐Oppenheimer Pola , Kohn Peter , Langford Richard M. , Steiner Ullrich 
Published: June 2012

AbstractThe control of semi‐crystalline polymers in thin films and in micrometer‐sized patterns is attractive for (opto‐)electronic applications. Electro‐hydrodynamic lithography (EHL) enables the structure formation of organic crystalline materials on the micrometer length scale while at the same time exerting control over crystal orientation. This gives rise to well‐defined micro‐patterned arrays of uniaxially aligned polymer crystals. This study explores the interplay of EHL structure formation with crystal alignment and studies the mechanisms that give rise to crystal orientation in EHL‐generated structures.
pH‐Controlled Delivery of Doxorubicin to Cancer Cells, Based on Small Mesoporous Carbon Nanospheres
Authors: Zhu Jie , Liao Lei , Bian Xiaojun , Kong Jilie , Yang Pengyuan , Liu Baohong 
Published: June 2012

AbstractMesoporous carbon nanospheres (MCNs) with small diameters of ≈90 nm are developed as an efficient transmembrane delivery vehicle of an anticancer drug, doxorubicin (DOX). MCNs exhibit a high loading capacity toward DOX due to hydrophobic interactions and the supramolecular π stacking between DOX and the carbonaceous structures, on which the pH‐dependent drug release are successfully achieved. Specifically, DOX can be loaded onto MCNs in basic solution and in a physiological pH range, while release occurs in acidic solution in its ionized state. By effective passive and active targeting, MCNs can be readily internalized into HeLa cells, where the carried DOX can be efficiently released in the acidic microenvironment of the tumors for further therapy. The endocytosis and cytotoxicity of DOX@MCNs toward HeLa cells are investigated by confocal microscopy and MTT assay. This smart pH‐dependent drug loading and release property of DOX@MCNs makes it possible to reduce the cytotoxicity to normal tissues during circulation in the body since the normal physiological pH is ≈7.4.
Doxorubicin‐Conjugated Mesoporous Magnetic Colloidal Nanocrystal Clusters Stabilized by Polysaccharide as a Smart Anticancer Drug Vehicle
Authors: Li Dian , Tang Jing , Wei Chuan , Guo Jia , Wang Shilong , Chaudhary Deeptangshu , Wang Changchun 
Published: June 2012

AbstractFabrication of magnetic nanocarriers that demonstrate enhanced biocompatibility and excellent colloidal stability is critical for the application of magnetic‐motored drug delivery, and it remains a challenge. Herein, a novel approach to synthesize mesoporous magnetic colloidal nanocrystal clusters (MMCNCs) that are stabilized by agarose is described; these clusters demonstrate high magnetization, large surface area and pore volume, excellent colloidal stability, enhanced biocompatibility, and acid degradability. The hydroxyl groups of agarose, which cover the surface of the magnetic nanocrystals, are modified with vinyl groups, followed by click reaction with mercaptoacetyl hydrazine to form the terminal hydrazide (–CONHNH2). The anticancer agent doxorubicin (DOX) is then conjugated to MMCNCs through a hydrazone bond. The resulting hydrazone is acid cleavable, thereby providing a pH‐sensitive drug release capability. This novel carrier provides an important step towards the construction of a new family of magnetic‐motored drug‐delivery systems. The experimental results show that the release rate of DOX from the DOX‐conjugated MMCNCs (MMCNCs‐DOX) is dramatically improved at low pH (tumor cell: pH 4–5 in the late stage of endolysosome and pH 5–6 from the early to late endosome), while almost no DOX is released at neutral pH (blood plasma). The cell cytotoxicity of the MMCNCs‐DOX measured by MTT assay exhibits a comparable antitumor efficacy but lower cytotoxicity for normal cell lines, when measured against the free drug, thus achieving the aim of reducing side effects to normal tissues associated with controlled drug release.
A Controllable Chiral Molecular Machine: Movement on Molecular Level
Authors: Yang Wenlong , Li Yongjun , Zhang Jianhong , Chen Nan , Chen Songhua , Liu Huibiao , Li Yuliang 
Published: June 2012

AbstractWith the view to develop new chiral molecular switches, a new pH‐controlled bistable chiral [3]rotaxane with a binaphthalene as chiral moiety is synthesized and characterized. The movement of the macrocycle DB24C8 along the thread tunes the dihedral angle between the two naphthalene rings and supplies tunable circular dichroism output signals.
Effects of Reducing Gas on Swelling and Iron Whisker Formation during the Reduction of Iron Oxide Compact
Authors: Wang Haitao , Sohn Hong Yong 
Published: June 2012

AbstractThe effects of different types of reducing gas on swelling and iron whisker formation during the reduction of iron oxide compacts were investigated. The compacts sintered in air at 1273 K were reduced at 1173 K in different reducing atmospheres. The results indicated that catastrophic swelling can happen in CO but not when H2 is present in the reducing gas mixture. Scanning electron microscope (SEM) micrographs showed that catastrophic swelling was caused by a large amount of long iron whiskers formed during the reduction. The presence of N2 and CO2 in CO changed the amount of long iron whiskers and its distribution, which determined the extent of swelling.