bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geometrical dependence of viscosity of polymethylmethacrylate melt in capillary flow
Authors: Lin Xiang , Kelly Adrian , Ren Dongyun , Woodhead Mike , Coates Phil , Wang Kuisheng 
Published: June 2013

ABSTRACTThe shear viscosity of polymethylmethacrylate (PMMA) melt is particularly investigated by using a twin‐bore capillary rheometer at four temperatures of 210, 225, 240, and 255°C with different capillary dies. Experimental results show that the geometrical dependence of shear viscosity is significantly dependent on melt pressure as well as melt temperature. The measured shear viscosity increases with the decrease of die diameter at lower temperatures (210 and 225°C) but decreases with the decrease of die diameter at higher temperatures (240 and 255°C). Based on the deviation of shear viscosity curves and Mooney method, negative slip velocity is obtained at low temperatures and positive slip velocity is obtained at high temperatures, respectively. Geometrical dependence and pressure sensitivity of shear viscosity as well as temperature effect are emphasized for this viscosity deviation. Moreover, shear viscosity curve at 210°C deviates from the power law model above a critical pressure and then becomes less thinning. Mechanisms of the negative slip velocity at low temperatures are explored through Doolittle viscosity model and Barus equation, in which the pressure drop is used to obtain the pressure coefficient by curve fitting. Dependence of pressure coefficient on melt temperature suggests that the pressure sensitivity of shear viscosity is significantly affected by temperature. Geometrical dependence of shear viscosity can be somewhat weakened by increasing melt temperature. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3384–3394, 2013
Highly Efficient Synthesis of Heterocyclic and Alicyclic β2‐Amino Acid Derivatives by Catalytic Asymmetric Hydrogenation
Authors: Li Lanning , Chen Bin , Ke Yuanyuan , Li Qing , Zhuang Yue , Duan Kun , Huang Yichun , Pang Jiyan , Qiu Liqin 
Published: June 2013

AbstractA valuable class of new heterocyclic and alicyclic prochiral α‐aminomethylacrylates has been conveniently synthesized through a three‐step transformation involving a Baylis–Hillman reaction, O‐acetylation, and a subsequent allylic amination. The corresponding novel β2‐amino acid derivatives were prepared with excellent enantioselectivities and high yields by catalytic asymmetric hydrogenation using the catalyst rhodium(Et‐Duphos) (Et‐Duphos=2′,5′,2′′,5′′‐tetraethyl‐1,2‐bis(phospholanyl)benzene)) under mild reaction conditions (up to 99 % ee and S/C=1000). The influence of the substrate on the enantioselectivity and reactivity is investigated, and the most suitable substrate configuration for the highly efficient enantioselective hydrogenation of β‐substituted α‐aminomethylacrylates under the Rh–Duphos system is reported. The current protocol provides a very practical, facile, and scalable method for the preparation of heterocyclic and alicyclic β2‐amino acids and their derivatives.
Allylation Reactions of Aldehydes with Allylboronates in Aqueous Media: Unique Reactivity and Selectivity that are Only Observed in the Presence of Water
Authors: Kobayashi Shū , Endo Toshimitsu , Yoshino Takumi , Schneider Uwe , Ueno Masaharu 
Published: June 2013

AbstractZn(OH)2‐catalyzed allylation reactions of aldehydes with allylboronates in aqueous media have been developed. In contrast to conventional allylboration reactions of aldehydes in organic solvents, the α‐addition products were obtained exclusively. A catalytic cycle in which the allylzinc species was generated through a B‐to‐Zn exchange process is proposed and kinetic studies were performed. The key intermediate, an allylzinc species, was detected by HRMS (ESI) analysis and by online continuous MS (ESI) analysis. This analysis revealed that, in aqueous media, the allylzinc species competitively reacted with the aldehydes and water. An investigation of the reactivity and selectivity of the allylzinc species by using several typical allylboronates (6a, 6b, 6c, 6d) clarified several important roles of water in this allylation reaction. The allylation reactions of aldehydes with allylboronic acid 2,2‐dimethyl‐1,3‐propanediol esters proceeded smoothly in the presence of catalytic amounts of Zn(OH)2 and achiral ligand 4d in aqueous media to afford the corresponding syn‐adducts in high yields with high diastereoselectivities. In all cases, the α‐addition products were obtained and a wide substrate scope was tolerated. Furthermore, this reaction was applied to asymmetric catalysis by using chiral ligand 9. Based on the X‐ray structure of the Zn‐9 complex, several nonsymmetrical chiral ligands were also found to be effective. This reaction was further applied to catalytic asymmetric alkylallylation, chloroallylation, and alkoxyallylation processes and the synthetic utility of these reactions has been demonstrated.
Systematic review and meta-analysis of liver resection for metastatic melanoma
Authors: Aubin J-M , Rekman J , Vandenbroucke-Menu F , Lapointe R , Fairfull-Smith R J , Mimeault R , Balaa F K , Martel G 
Published: June 2013

AbstractBackgroundThe multidisciplinary management of metastatic melanoma now occasionally includes major hepatic resection. The objective of this work was to conduct a systematic review of the literature on liver resection for metastatic melanoma.MethodsMEDLINE, Embase, the Cochrane Library and Scopus were searched (1990 to December 2012). Studies with at least ten patients undergoing liver resection for metastatic melanoma were included. Data on the outcomes of overall survival (OS) and/or disease-free survival (DFS) were abstracted and synthesized. Hazard ratios (HRs) were derived from survival curves and subjected to meta-analysis using random-effects models.ResultsTwenty-two studies involving 579 patients (13 per cent weighted resection rate) who underwent liver resection were included. Study quality was poor to moderate. Median follow-up ranged from 9 to 59 months. Median DFS ranged from 8 to 23 months, and median OS ranged from 14 to 41 months (R0, 22–66 months, R2, 10–16 months; R0versus R1/R2: HR 0.52, 95 per cent confidence interval (c.i.) 0.37 to 0.73). The OS rate was 56–100 per cent at 1 year, 34–53 per cent at 3 years and 11–36 per cent at 5 years. Median OS with non-operative management ranged from 4 to 12 months. Comparison of OS with resection and non-operative management favoured resection (HR 0.32, 95 per cent c.i. 0.22 to 0.46).ConclusionRadical resection of liver metastases from melanoma appears to improve overall survival compared with non-operative management or incomplete resection, but this observation requires future confirmation as selection bias may have confounded the results.
Sustained and transient attentional processes modulate neural predictors of memory encoding in consecutive time periods
Authors: Padovani Tullia , Koenig Thomas , Eckstein Doris , Perrig Walter J. 
Published: June 2013

AbstractMemory formation is commonly thought to rely on brain activity following an event. Yet, recent research has shown that even brain activity previous to an event can predict later recollection (subsequent memory effect, SME). In order to investigate the attentional sources of the SME, event‐related potentials (ERPs) elicited by task cues preceding target words were recorded in a switched task paradigm that was followed by a surprise recognition test. Stay trials, that is, those with the same task as the previous trial, were contrasted with switch trials, which included a task switch compared to the previous trial. The underlying assumption was that sustained attention would be dominant in stay trials and that transient attentional reconfiguration processes would be dominant in switch trials. To determine the SME, local and global statistics of scalp electric fields were used to identify differences between subsequently remembered and forgotten items. Results showed that the SME in stay trials occurred in a time window from 2 to 1 sec before target onset, whereas the SME in switch trials occurred subsequently, in a time window from 1 to 0 sec before target onset. Both SMEs showed a frontal negativity resembling the topography of previously reported effects, which suggests that sustained and transient attentional processes contribute to the prestimulus SME in consecutive time periods.
Bifunctional Iron Complexes: Efficient Catalysts for CO and CN Reduction in Water
Authors: Mérel Delphine S. , Elie Margaux , Lohier Jean‐François , Gaillard Sylvain , Renaud Jean‐Luc 
Published: June 2013

AbstractThe application of bifunctional iron complexes for the hydrogenation of polarized CX bonds is reported. Two modified Knölker complexes bearing ionic fragments were synthesized and fully characterized. With these well‐defined complexes, the reaction proceeded under mild conditions in pure water, and various alcohols and amines were isolated in good yields. Compared with hydrogenation in organic solvents, better reactivities were observed.
Exploiting Multivalent Nanoparticles for the Supramolecular Functionalization of Graphene with a Nonplanar Recognition Motif
Authors: Brunetti Fulvio G. , Isla Helena , Aragó Juan , Ortí Enrique , Pérez Emilio M. , Martín Nazario 
Published: June 2013

AbstractThe supramolecular modification of planar graphene with the geometrically mismatched, curved 9,10‐di(1,3‐dithiole‐2‐ylidene)‐9,10‐dihydroanthracene (exTTF) molecule is demonstrated. The exTTF–graphene interaction is governed by π–π and CH–π interactions, with a negligible contribution from charge transfer. We amplified these weak forces through multivalent gold nanoparticles. Our results show that planarity is not a prerequisite for recognition motifs for graphene.
Asymmetric Synthesis of 2,4,5‐Trisubstituted Δ2‐Thiazolines
Authors: Bengtsson Christoffer , Nelander Hanna , Almqvist Fredrik 
Published: June 2013

AbstractΔ2‐Thiazolines are interesting heterocycles that display a wide variety of biological characteristics. They are also common in chiral ligands used for asymmetric syntheses and as synthetic intermediates. Herein, we present asymmetric routes to 2,4,5‐trisubstituted Δ2‐thiazolines. These Δ2‐thiazolines were synthesized from readily accessible/commercially available α,β‐unsaturated methyl esters through a Sharpless asymmetric dihydroxylation and an O→N acyl migration reaction as key steps. The final products were obtained in good yields with up to 97 % enantiomeric excess.
Predictability of Enantiomeric Chromatographic Behavior on Various Chiral Stationary Phases Using Typical Reversed Phase Modeling Software
Authors: Wagdy Hebatallah A. , Hanafi Rasha S. , El‐Nashar Rasha M. , Aboul‐Enein Hassan Y. 
Published: June 2013

ABSTRACTPharmaceutical companies worldwide tend to apply chiral chromatographic separation techniques in their mass production strategy rather than asymmetric synthesis. The present work aims to investigate the predictability of chromatographic behavior of enantiomers using DryLab HPLC method development software, which is typically used to predict the effect of changing various chromatographic parameters on resolution in the reversed phase mode. Three different types of chiral stationary phases were tested for predictability: macrocyclic antibiotics‐based columns (Chirobiotic V and T), polysaccharide‐based chiral column (Chiralpak AD‐RH), and protein‐based chiral column (Ultron ES‐OVM). Preliminary basic runs were implemented, then exported to DryLab after peak tracking was accomplished. Prediction of the effect of % organic mobile phase on separation was possible for separations on Chirobiotic V for several probes: racemic propranolol with 97.80% accuracy; mixture of racemates of propranolol and terbutaline sulphate, as well as, racemates of propranolol and salbutamol sulphate with average 90.46% accuracy for the effect of percent organic mobile phase and average 98.39% for the effect of pH; and racemic warfarin with 93.45% accuracy for the effect of percent organic mobile phase and average 99.64% for the effect of pH. It can be concluded that Chirobiotic V reversed phase retention mechanism follows the solvophobic theory. Chirality 25:506–513, 2013. © 2013 Wiley Periodicals, Inc.
A Highly Diastereoselective Three‐component Domino Reaction in Water Yielding Poly‐substituted 4,5‐Dihydropyrroles
Authors: Tong Guangjing , Xu Haiwei , Fan Wei , Jiang Bo , Wang Shuliang , Tu Shujiang 
Published: June 2013

AbstractAn efficient methodology for highly diastereoselective synthesis of poly‐substituted 4,5‐dihydropyrrole derivatives from readily available common reactants in water has been developed. During domino processes, the formation of pyrrole skeleton and its C2‐hydroxylation and C3‐arylamination were readily achieved via metal‐free [3+2] heterocyclization in a one‐pot operation.
Synthesis of Guanidines from Amines and Carbodiimides Catalyzed by Mono‐Indenyl‐Ligated Rare Earth Metal Bis(silylamide) Complexes
Authors: Chen Jue , Wang Yibin , Luo Yunjie 
Published: June 2013

AbstractNucleophilic addition of primary aromatic amines to carbodiimides in the presence of catalytic amount of the mono‐indenyl‐ligated rare earth metal bis(silylamide) complexes (C9H6CMe2CH2C5H4N‐α)Ln[N(SiHMe2)2]2 at room temperature afforded efficiently a series of guanidines with a wide spectrum of substituents on the nitrogen atoms.
Assessing the potential cost‐effectiveness of retesting IHC0, IHC1+, or FISH‐negative early stage breast cancer patients for HER2 status
Authors: Garrison Louis P. , Lalla Deepa , Brammer Melissa , Babigumira Joseph B. , Wang Bruce , Perez Edith A. 
Published: June 2013

BACKGROUNDFluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) tests are commonly used to assess human epidermal growth factor 2 (HER2) status of tumors in patients with breast cancer. This analysis evaluates the likely cost‐effectiveness of expanded retesting to assess HER2 tumor status in women with early stage breast cancer.METHODSWe developed a decision‐analytic model to estimate the incremental cost‐effectiveness ratio (ICER) of expanded reflex testing from a US payer perspective. Expanded reflex testing is defined as retesting tumor specimens from patients whose tumors are IHC0, IHC1+, or FISH‐negative on their first test. In the base case, we assumed that 80% of patient tumors are initially IHC‐tested and 20% are FISH‐tested. Testing outcomes for IHC and FISH with and without retesting were based on published meta‐analyses. The cost of tests and treatment and the long‐term health outcomes were obtained from the literature.RESULTSIn the base case, we estimated that 2.27% of women who received expanded reflex testing would be HER2‐positive and receive trastuzumab treatment: the projected ICER was $36,721 per life year or $39,745 per quality‐adjusted life year (QALY). This varied between $47,100 per QALY and $35,500 per QALY if we assumed that 1%‐8% of patients retested were then HER2+, respectively. The results of deterministic and probabilistic sensitivity analysis were robust. This strategy would result in 4700 (2000‐17,000) patients being eligible to receive trastuzumab treatment annually.CONCLUSIONSRetesting patients who are IHC0, IHC1+, or FISH‐negative is projected to be a cost‐effective clinical strategy. Cancer 2013;119:3113–3122. © 2013 American Cancer Society.
Contactless magnetic gear for robot control application
Authors: Komiyama Hiroki , Uchimura Yutaka 
Published: June 2013

SummaryThis paper describes the application of a magnetic gear to a robot by fulfilling the essential requirements for a robot control, which are velocity control, position control, and force control. A magnetic gear is a transmission device that realizes contactless torque transmission by applying a magnetic force. When using a magnetic gear, cogging torque and spring characteristics need to be considered. In this paper, we introduce an approximate model of cogging torque. This model is used for velocity control to attenuate the disturbance due to cogging torque. In the case of position control, the oscillations due to the spring effect of the magnetic attractive force become a problem. To reduce the adverse effect due to these oscillations, resonance ratio control is applied. We also propose to use a magnetic gear for realizing force sensorless bilateral control of teleoperation. Because of the frictionless transmission of a magnetic gear, the force sensorless estimation of a reaction force can be realized using a reaction force observer. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(4): 32–41, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22414
A grid‐connected inverter with virtual synchronous generator model of algebraic type
Authors: Hirase Yuko , Abe Kazuhiro , Sugimoto Kazushige , Shindo Yuji 
Published: June 2013

SummaryThis paper presents experimental results on a grid‐connected inverter. The control of the inverter is based on a virtual synchronous generator model of algebraic type. When using the virtual synchronous generator model of algebraic type, there is no evidence for satisfactory operation with unbalanced load and nonlinear load, because the generator models are constructed under the assumption that the load is linear and balanced. By choosing the feedback control loop gain appropriately, satisfactory operation is achieved even if an unbalanced and nonlinear load is connected. Experimental results show that the power controls, active and reactive, are achieved preferably in grid‐connecting mode. Smooth transitions are also achieved from the connected mode to the island mode. The inverter can operate satisfactorily when the unbalanced load is connected. Harmonic analysis is performed with a three‐phase full‐wave rectifier connected as a nonlinear load. The harmonic current is supplied by the inverter and its output LC filter. It is shown that the harmonic current is supplied mainly by the inverter and that the voltage waveform is acceptable for practical use. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(4): 10–21, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22428
Cobalt–Magnesium and Iron–Magnesium Complexes with Weakened Dinitrogen Bridges
Authors: Dugan Thomas R. , MacLeod K. Cory , Brennessel William W. , Holland Patrick L. 
Published: June 2013

AbstractThe cooperative binding of N2 by late transition and main‐group metals is a promising strategy for N–N bond weakening and activation. We report the use of activated Rieke magnesium for the reduction of iron and cobalt complexes supported by bulky β‐diketiminate ligands. The binding of N2 is accompanied by the assembly of a linear M–NN–Mg–NN–M (M = Co, Fe) core with weakened N–N bonds, as judged by infrared spectroscopy. Both the cobalt and iron complexes require tetrahydrofuran (THF) solvent, because of Mg–THF binding. The cobalt complex can be isolated as a pure solid, but the iron complex is stable only in solution. These results demonstrate the correlation between the binding mode and N–N weakening in heterobimetallic N2 complexes.
Two‐Dimensional Iron(II) Networks – Guest‐Dependent Structures and Spin‐Crossover Behaviors
Authors: Yang Feng‐Lei , Chen Ming‐Guang , Li Xiu‐Ling , Tao Jun , Huang Rong‐Bin , Zheng Lan‐Sun 
Published: June 2013

AbstractFour compounds with general formula [Fe(4‐bphz)2(NCS)2]·X [4‐bphz = 1,2‐bis(pyridin‐4‐ylmethylene)hydrazine; X = 2H2O·2CH3CN (1·CH3CN), 4CH3COCH3 (2·CH3COCH3), 2.5C10H8 (3·C10H8), 2C6H5NO2 (4·C6H5NO2)] were synthesized and characterized. These compounds contain 2D gridlike networks that are diversely stacked or self‐interpenetrated depending on the inclusive guest molecules. Magnetic studies showed that 1·CH3CN undergoes a two‐step and almost complete spin transition and 2·CH3COCH3 showed an incomplete transition, whereas 3·C10H8 and 4·C6H5NO2 are paramagnetic in the whole temperature range. Correlations between structures and magnetic properties revealed that the size and shape of the guest molecules exerted great influence on the conformation of the ligand and the 3D structures of the complexes and, hence, spin‐crossover behaviors.
Di‐ and Trinuclear Zinc and Cobalt Complexes and Their Reactivity towards Dioxygen
Authors: Siewert Inke , Sietzen Malte , Dechert Sebastian , Demeshko Serhiy 
Published: June 2013

AbstractA new ligand L– with two adjacent pyrazole–pyridine moieties, which are linked by a CHO– unit was developed and utilised to synthesise three multinuclear metal complexes. The reaction of HL with NEt3 and zinc(II) halides or cobalt(II) chloride leads to complexes of the type [M2L2]2+ (M = Co, Zn). Temperature‐dependent magnetic measurement of [Co2L2](PF6)2 (I) showed a ferromagnetic coupling of the Co ions. Subsequently, the reactivity of these complexes with O2 was investigated. Complex I reacts with O2 to form a cobalt(II) complex in which the ligand is oxygenated at the central carbon atom, that is, a gem‐diol is formed. As [Zn2L2](PF6)2 (II) does not react with O2, the Co ions mediate the oxygenation of the ligand in [Co2L2]2+. The reaction of Zn(OAc)2 with HL under inert conditions leads to the formation of the trinuclear complex [Zn3L(OAc)5] (III), which decomposes in air. Further investigation showed that O2 causes ligand oxidation in the central carbon position, which leads to the corresponding ketone upon decomplexation. The primary decomposition products are presumably gem‐diolate zinc species. These results point to different reaction mechanisms for the activation of dioxygen by I and III.
A Uranyl Hybrid Compound Designed from Urea‐Bearing Dipropionic Acid
Authors: Shu Yu‐Bo , Xu Cong , Liu Wei‐Sheng 
Published: June 2013

AbstractA uranyl‐urea‐bearing dipropionate hybrid compound, in which the two acid groups are coordinated in different modes and the urea group serves as both a coordination functionality and a supramolecular synthon, is prepared. The effect of hydrogen‐bonding interactions on the luminescence properties of the compound was explored by lifetime measurements. Thermogravimetric analyses were performed under a nitrogen atmosphere and in air. The “uranophilicity” of this urea‐bearing ligand was examined by competition experiments in alkaline spring water.