bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Characterisation of Low‐Coordinate Transition‐Metal Complexes Stabilised by Sterically Demanding Carbazolido Ligands
Authors: Ashley Andrew E. , Cowley Andrew R. , Green Jennifer C. , Johnston David R. , Watkin David J. , Kays Deborah L. 
Published: May 2009

AbstractThe synthesis and characterisation of the homoleptic transition‐metal complexes (1,8‐Ph2‐3,6‐Me2C12H4N)2M (M = Cr, 1; M = Mn, 2; M = Fe, 3; M = Co, 4) are described. Formally two‐coordinate, the solid‐state structures of 2 and 3 reveal near‐linear N–M–N geometries and significant bending of the flanking phenyl groups towards the metal centres. Solid‐state magnetic measurements reveal high spin metal centres in 1–4; computational calculations for the model complexes M(1,8‐Ph2C12H6N)2 (M = Cr–Co) confirm the presence of high‐spin configurations within these bis‐carbazolido compounds and an orbital ordering of δ < π < σ for these systems.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Templated Synthesis and Site‐Selective Conversion of Completely Nonsymmetrical Bis‐Metallosalphen Complexes
Authors: Castilla Ana M. , Curreli Simona , Carretero Nina M. , Escudero‐Adán Eduardo C. , Benet‐Buchholz Jordi , Kleij Arjan W. 
Published: May 2009

AbstractA metal‐templated, stepwise approach toward fully nonsymmetrical bis‐metallosalphen complexes is described. The synthesis comprises the selective monometalation of diimine precursors and subsequent introduction of the second metal ion by using various salicylaldehyde reagents. In the case of a bis‐Zn(salen) derivative, the presence of different peripheral substituents on the two metallosalen units gave rise to a large difference in kinetic stability, which was used to selectively demetalate the more labile site. This result shows promise for the preparation of heterobimetallic structures. The first X‐ray molecular structure of a completely nonsymmetrical bis‐salphen complex is also reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Ternary Porphyrinato HfIV and ZrIV Polyoxometalate Complexes
Authors: Falber Alexander , Burton‐Pye Benjamin P. , Radivojevic Ivana , Todaro Louis , Saleh Raihan , Francesconi Lynn C. , Drain Charles Michael 
Published: May 2009

AbstractWe report a facile, high‐yield synthesis and characterization of discrete, ternary porphyrin–metal–polyoxometalate (por–M–POM) complexes where a group IV transition‐metal ion is bound both to the porphyrin core and to the lacunary site of a Keggin POM, PW11O39–7. The remarkably robust complexes exploit the fact that HfIV and ZrIV are 7–8 coordinate and reside outside the plane of the porphyrin macrocycle, thus enabling the simultaneous coordination to meso‐tetraphenylporphyrin (tpp) or meso‐tetra(4‐pyridyl)porphyrin (tpyp) and to the defect site in the Keggin framework. The physical properties of the (tpp)Hf(PW11O39)[tba]5, (tpyp)Hf(PW11O39)[tba]5, and (tpp)Zr(PW11O39)[tba]5 complexes are similar because the metal ions have similar oxidation states and coordination chemistry. This architecture couples the photonic properties of the porphyrin to the POM because the metal ion is incorporated into both frameworks. Thus, the ternary complexes can serve as a basis for the characterization of HfIV and ZrIV porphyrins bound to oxide surfaces through the group IV metal ions. The Hf(por) and Zr(por) bind strongly to TiO2 nanoparticles and indium tin oxide (ITO) surfaces, but significantly less binds to crystalline SiO2 or TiO2 surfaces. Together, the strong binding of the metalloporphyrins to the POM, nanoparticles, and the ITO surfaces, and paucity of binding to crystalline surfaces, suggests that the three‐to‐four open coordination sites on the Hf(por) and Zr(por) are predominantly bound at surface defect sites. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Studies towards the Total Synthesis of (–)‐Caulerpenynol, a Toxic Sesquiterpenoid of the Green Seaweed Caulerpa taxifolia
Authors: Commeiras Laurent , Thibonnet Jérôme , Parrain Jean‐Luc 
Published: May 2009

AbstractThe first diastereoselective synthesis of the antimicrobial and cytotoxic agent (–)‐caulerpenynol (2) was achieved in relatively few steps from commercially available (S)‐malic acid. Highlights of this synthesis include the nonracemization of the sensitive α‐hydroxy ketone moiety and the proper choice of the protecting groups for critical last deprotection step. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis of 2‐Azetidinones Incorporating Carbenechromium(0) Moieties and Their Use in the Preparation of Penicillin‐ and Cephalosporin‐Containing Peptides
Authors: Sierra Miguel A. , Rodríguez‐Fernández Mamen , Casarrubios Luis , Gómez‐Gallego Mar , Mancheño María José 
Published: May 2009

AbstractA series of β‐lactams incorporating a carbenechromium(0) moiety in their structures have been prepared. These stable compounds are suitable precursors for the preparation of α‐amino esters, dipeptides and tripeptides tethered to a 2‐azetidinone ring. The methodology has also been extended to the synthesis of carbenechromium(0) complexes of penicillin G, cephalosporin and 6‐aminopenicillanic acid. All these new metalla‐β‐lactam derivatives are stable compounds and can be transformed into antibiotic structures with tripeptide side‐chains. The methodology relies on the compatibility of the β‐lactam ring with the carbenechromium(0) moiety and on the stability of the four‐membered ring during the photocarbonylation of the resulting chromium complex.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
An Easy and Multigram‐Scale Synthesis of Versatile AA‐ and AB‐Type m‐Terphenylenes as Building Blocks for Kinked Polyphenylenes
Authors: Kissel Patrick , Breitler Simon , Reinmüller Viktoria , Lanz Patrick , Federer Lukas , Schlüter A. Dieter , Sakamoto Junji 
Published: May 2009

AbstractA set of m‐terphenylenes having a readily functionalizable hydroxy group as well as either symmetric AA‐type or unsymmetric AB‐type halide termini have been prepared on a several‐gram scale. The synthesis was carried out on the basis of the Suzuki–Miyaura cross‐coupling in combination with a TMS masking strategy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Long open tubular molecule imprinted polymer capillary columns with excellent separation efficiencies in chiral and non‐chiral separation by capillary electrochromatography
Authors: Zaidi Shabi Abbas , Cheong Won Jo 
Published: May 2009

AbstractLong open tubular S‐ketoprofen molecule imprinted polymer capillary columns (1, 2, and 3 m) with the number of theoretical plates (N) over a million for both chrial and non‐chiral CEC separation have been prepared. Chiral separation of racemic ketoprofen and non‐chiral separation of other profen drugs have been achieved with excellent efficiency and good selectivity after optimization of the chromatographic conditions. The N value per column was not proportional to the effective column length although it was increased with the column length. This study has shown the outstanding prospect of the strategy to form a porous and rugged open tubular layer in a moderately long (1 m) capillary column in molecule imprinted polymer‐CEC studies.
Electrophoretic behaviors of human hepatoma HepG2 cells
Authors: Hsu Jyh‐Ping , Ku Ming‐Hong , Yang Li‐Chia , Lu Jui‐Nan , Young Tai‐Horng , Tseng Shiojenn 
Published: May 2009

AbstractThe electrophoretic mobility of HepG2 cells was measured and a charge‐regulated model was proposed to simulate the results obtained. Here, a cell was simulated by a rigid core and an ion‐penetrable membrane layer containing both acidic and basic functional groups. The influences of the key parameters, including the pH, the ionic strength, the thickness of the membrane layer of a cell, the density and the dissociation constant of the dissociable functional groups in the membrane layer, and the binding constant of divalent cations on the electrophoretic mobility of a cell were investigated. In particular, the role of the buffer used in the experiment was discussed; this effect was neglected in almost all the relevant theoretical analyses in the literature. We showed that the binding ability of divalent cations to the dissociated functional groups in the membrane layer of a cell ranks as Ca2+>Mg2+>hexamethonium.
Enhanced detection in capillary electrophoresis: Example determination of serum mycophenolic acid
Authors: Shihabi Zak K. 
Published: May 2009

AbstractIn order to overcome the poor absorbency detection limits in CE, two simple strategies were combined to increase the amount of the sample injected: a long capillary to hold extra sample while leaving adequate room for the separation and acetonitrile stacking, which concentrated the sample based on transient pseudo‐ITP. The combination of these two strategies yielded sensitivity comparable or better than that of the HPLC with good separation and with better theoretical plate number. The analysis of mycophenolic acid, a common immunosuppressant drug, in serum was used here as an example to illustrate this enhanced detection and its applicability to therapeutic drug monitoring. Acetonitrile was used to remove serum proteins followed by direct injection filling 5–21% of the capillary volume and separation in a borate buffer. The overall CE method compared well to an assay by HPLC as far as sample preparation, correlation coefficient, and especially sensitivity of detection.
Capillary electrophoretic study of small, highly sulfated, non‐sugar molecules interacting with antithrombin
Authors: Liang Aiye , Raghuraman Arjun , Desai Umesh R. 
Published: May 2009

AbstractAffinity CE (ACE) was used to study interactions of small, highly sulfated, aromatic molecules with antithrombin (AT). The high charge density of the small molecules induces differential migration of the complex resulting in a versatile method of assessing binding affinities, nature of interactions and site of binding on the inhibitor. Scatchard analysis of the interaction of three tetrahydroisoquinoline‐based polysulfated molecules with AT results in monophasic profiles with affinities in the range of 40–60 μM in 20 mM sodium phosphate buffer, pH 7.4. For a pentasulfated molecule, a biphasic profile with affinities of 4.7 and 30 μM was observed. Measurement of KD as a function of ionic strength of the medium indicated that ionic and non‐ionic forces contribute 2.4 and 1.9 kcal/mol, respectively, at pH 7.4 and 100 mM NaCl. Competitive binding studies showed that the tetrahydroisoquinoline‐based molecules do not compete with a high‐affinity heparin pentasaccharide. In contrast, the affinity of these tetrahydroisoquinoline derivatives decreases dramatically in the presence of an extended heparin‐binding site ligand. Overall, ACE analysis of small, sulfated aromatic molecules interacting with AT is relatively easy and obviates the need for an external signal, e.g. fluorescence, for monitoring the interaction. In addition to affording biochemical knowledge, the small sample requirement and fast analysis time of ACE could be particularly advantageous for high‐throughput screening of potential anticoagulants.
Insulator‐based dielectrophoretic separation of small particles in a sawtooth channel
Authors: Chen Kang Ping , Pacheco Jose Rafael , Hayes Mark. A. , Staton Sarah J. R. 
Published: May 2009

AbstractInsulator‐based dielectrophoretic separation of small particles in a sawtooth channel is studied in the limit of dilute concentration. Pathlines for the movements of infinitesimal particles are constructed and the geometric changes of these pathlines are used to establish the criterion for blocking and trapping particles with different physical properties. The sharp corners of the sawtooth channel create much stronger dielectrophoretic force than channels with smooth corners for blocking particle movements. Particle blocking and trapping depend on particle properties and the geometry of the device. It is shown that once the channel geometric aspect ratios are specified, the blocking criterion depends on only a single dimensionless parameter C defined in terms of the particle mobility ratio (dielectrophoretic versus electrokinetic), the applied voltage and the spacing between the teeth. Selective blocking and trapping of particles can be realized by varying the geometry of the channel progressively. High‐resolution separation can be achieved by tuning the differential in the parameter C to a desired level.
Proteome alteration of early‐stage differentiation of mouse embryonic stem cells into hepatocyte‐like cells
Authors: Li Yan , Kang Xiaonan , Guo Kun , Li Xuefei , Gao Dongmei , Cui Jiefeng , Sun Lu , Yang Pengyuan , Liu Yinkun 
Published: May 2009

AbstractTo explore the molecular basis of inducible differentiation of embryonic stem cells into hepatocyte‐like cells, a proteomic strategy was utilized to examine the global protein expression alterations after early‐stage differentiation of a mouse D3 embryonic stem (ES) cell line along hepatic lineage. The undifferentiated D3 cells were treated stepwise with combinations of defined chemicals and growth factors. The differentiated cells were identified by hepatocyte‐like morphology, expressed liver‐specific markers as well as the evidence of glycogen storage. The subsequent proteomic separation and identification were performed with 2‐DE followed by MALDI‐TOF‐MS/MS analysis. Of the 119 differentially displayed protein spots analyzed, 90 spots presenting 64 distinct proteins were finally identified. The interested protein expressions were validated by Western blotting such as albumin and cytokeratin‐8. Bioinformatic annotations indicated that this set of proteins was enriched with transcription, translation regulation and protein processing, energy/metabolism and chaperon functions. A part of them had been found to be involved in the differentiation of mouse ES cells. Interestingly, approximately 40% of these proteins had been previously reported as being dysregulated in hepatocellular carcinoma. It suggested that these changed proteins may be candidate regulators of ES cell differentiation, some of them may be specific to hepatic differentiation.
Analysing risk attitudes to time
Authors: Oliver Adam , Cookson Richard 
Published: May 2009

AbstractThe assumption of risk neutrality over discounted life years underlies the standard QALY model of individual preferences over health outcomes, and is thus implicitly assumed by NICE and other health technology advisory bodies worldwide. The primary objective of this article is to report a study to test the assumption in a convenience sample of 30 respondents with use of the probability equivalence version of the standard gamble. The results indicate considerable risk aversion over life years, and therefore call into question the standard assumption of risk neutrality in practical cost‐utility analyses (CUA). A secondary objective is to observe whether risk aversion can be reduced through the use of the lottery equivalents method, under the hypothesis that the gambling effect can be lessened with this instrument. In a separate convenience sample of 40 respondents, however, the observed level of risk aversion was at least that seen in the standard gamble. Further research is warranted to ascertain whether risk aversion over discounted life years is a generalisable concern. Copyright © 2009 John Wiley & Sons, Ltd.
Reuse of return flow from wetland paddy to supplement industrial water needs
Authors: Chang Yu‐Chuan , Lin Wei‐Taw , Hsu Nien‐Sheng , Kan Chun‐E. 
Published: May 2009

AbstractIn this paper a water reuse system in wetland paddy was simulated to supply water for industry. A two‐tank model was employed to represent the return flow of the wetland paddy. Historical data were used for parameter estimation and model verification. The simulation results show that the return flow from wetland paddy has potential benefit for water reuse. Under a series of water management strategies, about 87% of the total volume of return flow can supplement industrial water needs which decreases local water needs by about 22.4%. The strategies include increasing the volume of return flow through deepwater management practices, stabilizing the reuse of return flow in the purification unit through the regulated large‐capacity pond downstream, and harmonizing the supply‐and‐demand gap through a suitable cultivated paddy scale of the crop rotation pattern. Apart from meeting water needs at peak demand periods, the reuse of return flow is a quick‐response water supply solution. Accompanied by the series of water management strategies, water reliability and crop security can be achieved at the same time. Copyright © 2009 John Wiley & Sons, Ltd.
Effect of Filtered Cultures of Flagellate Ochromonas sp. on Colony Formation in Microcystis aeruginosa
Authors: Yang Zhen , Kong Fanxiang , Zhang Min , Yang Zhou , Yu Yang , Qian Shanqin 
Published: May 2009

AbstractThe possible effect of filtered cultures of flagellate Ochromonas sp. on colony formation in M. aeruginosa was investigated in this paper. The results show that filtered cultures of flagellates fed with M. aeruginosa could induce colony formation in M. aeruginosa. Furthermore, induction strength is clearly dependent on the concentration of flagellates and filtered cultures. However, no colonial M. aeruginosa was found in the treatments of filtered cultures of flagellates fed with Microcystis wesenbergii, filtered cultures of flagellate fed with Chlorella pyrenoidosa, and algae homogenates. This suggests that infochemicals released from flagellates fed with M. aeruginosa may be a trigger for colony formation in M. aeruginosa. The clearance rates of flagellates on algae were markedly decreased when they were cultivated with induced colonial M. aeruginosa. These indicate that colony formation in M. aeruginosa is a predator‐induced defense which could reduce predation risk from flagellates (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization and tribology of PEG‐like coatings on UHMWPE for total hip replacements
Authors: Kane Sheryl R. , Ashby Paul D. , Pruitt Lisa A. 
Published: May 2009

AbstractA crosslinked hydrogel coating similar to poly(ethylene glycol) (PEG) was covalently bonded to the surface of ultrahigh molecular weight polyethylene (UHMWPE) to improve the lubricity and wear resistance of the UHWMPE for use in total joint replacements. The chemistry, hydrophilicity, and protein adsorption resistance of the coatings were determined, and the wear behavior of the PEG‐like coating was examined by two methods: pin‐on‐disk tribometry to evaluate macroscale behavior, and atomic force microscopy (AFM) to simulate asperity wear. As expected, the coating was found to be highly PEG‐like, with ∼83% ether content by x‐ray photoelectron spectroscopy and more hydrophilic and resistant to protein adsorption than uncoated UHMWPE. Pin‐on‐disk testing showed that the PEG‐like coating could survive 3 MPa of contact pressure, comparable to that experienced by total hip replacements. AFM nanoscratching experiments uncovered three damage mechanisms for the coatings: adhesion/microfracture, pure adhesion, and delamination. The latter two mechanisms appear to correlate well with wear patterns induced by pin‐on‐disk testing and evaluated by attenuated total reflection Fourier transform infrared spectroscopy mapping. Understanding the mechanisms by which the PEG‐like coatings wear is critical for improving the behavior of subsequent generations of wear‐resistant hydrogel coatings. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res 2010
Dendritic cell responses to self‐assembled monolayers of defined chemistries
Authors: Shankar Sucharita P. , Petrie Timothy A. , García Andrés J. , Babensee Julia E. 
Published: May 2009

AbstractBiomaterial contact triggers dendritic cell (DC) maturation, to an extent depending on the biomaterial, ultimately enhancing an immune response toward associated antigens, implying a role for biomaterials as adjuvants. Self‐assembled monolayers (SAM) of alkanethiols on titanium/gold‐coated surfaces presenting different chemistries were used to study effects of biomaterial surface chemistry on DC maturation. Although DCs treated with OH, COOH, or NH2SAMs showed modest maturation, those treated with CH3SAMs were least mature, all based on cytospins, allostimulatory capacity, or maturation marker expression. Surprisingly, DCs treated with CH3SAMs secreted highest levels of proinflammatory tumor necrosis factor‐α (TNF‐α) or interleukin‐6 (IL‐6) but were least mature. Secretion of anti‐inflammatory mediators by DCs treated with CH3SAMs was not responsible for mitigating DC maturation under these conditions. Interestingly, elevated levels of apoptotic markers were measured associated with DCs and T cells upon CH3SAMs contact. Since phagocytosis of apoptotic DCs has strong immunosuppressive effects on DCs, more apoptotic DCs on CH3SAMs may account for lower DC maturation. Finally, higher expression of cytotoxic T lymphocyte associated antigen receptor‐4 (CTLA‐4) on T cells may imply a mechanism of T cell inhibition on CH3SAMs. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res 2010
Microcomputed tomography and microfinite element modeling for evaluating polymer scaffolds architecture and their mechanical properties
Authors: Alberich‐Bayarri Angel , Moratal David , Ivirico Jorge L. Escobar , Hernández José C. Rodríguez , Vallés‐Lluch Ana , Martí‐Bonmatí Luis , Estellés Jorge Más , Mano Joao F. , Pradas Manuel Monleón , Ribelles José L. Gómez , Salmerón‐Sánchez Manuel 
Published: May 2009

AbstractDetailed knowledge of the porous architecture of synthetic scaffolds for tissue engineering, their mechanical properties, and their interrelationship was obtained in a nondestructive manner. Image analysis of microcomputed tomography (μCT) sections of different scaffolds was done. The three‐dimensional (3D) reconstruction of the scaffold allows one to quantify scaffold porosity, including pore size, pore distribution, and struts' thickness. The porous morphology and porosity as calculated from μCT by image analysis agrees with that obtained experimentally by scanning electron microscopy and physically measured porosity, respectively. Furthermore, the mechanical properties of the scaffold were evaluated by making use of finite element modeling (FEM) in which the compression stress–strain test is simulated on the 3D structure reconstructed from the μCT sections. Elastic modulus as calculated from FEM is in agreement with those obtained from the stress–strain experimental test. The method was applied on qualitatively different porous structures (interconnected channels and spheres) with different chemical compositions (that lead to different elastic modulus of the base material) suitable for tissue regeneration. The elastic properties of the constructs are explained on the basis of the FEM model that supports the main mechanical conclusion of the experimental results: the elastic modulus does not depend on the geometric characteristics of the pore (pore size, interconnection throat size) but only on the total porosity of the scaffold. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009