bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shuttling Gold Nanoparticles into Tumoral Cells with an Amphipathic Proline‐Rich Peptide
Authors: Pujals Sílvia , Bastús Neus G. , Pereiro Eva , López‐Iglesias Carmen , Puntes Víctor F. , Kogan Marcelo J. , Giralt Ernest 
Published: March 2009

AbstractGolden bullets: The amphipathic proline‐rich cell‐penetrating peptide sweet arrow peptide (SAP) is able to transport 12 nm gold nanoparticles efficiently into HeLa cells, as observed by three microscopy techniques: transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM) and transmission X‐ray microscopy (TXM). Multiconjugation to such nanoparticles may provide a convenient method for unifying the key drug properties of high activity, capacity to home onto targets and delivery to therapeutic places of action.magnified imageCell‐penetrating peptides (CPPs) are a potential tool for intracellular delivery of different kinds of cargoes. Because of their growing use in nanobiomedicine, both for diagnostics and for treatment, metal nanoparticles are an interesting cargo for CPPs. Here, gold nanoparticles (AuNps) and the amphipathic proline‐rich peptide SAP have been used. Conjugation of the peptide onto the AuNps was achieved by addition of a cysteine to the SAP sequence for thiol chemisorption on gold, and the attachment was confirmed by visible spectroscopy, dynamic light scattering (DLS), ζ‐potential (ZP), stability towards ionic strength (as high as 1 M NaCl), X‐ray photoelectron spectroscopy (XPS) and high‐resolution transmission electron microscopy (HR‐TEM) coupled to electron energy loss spectroscopy (EELS). AuNp‐C‐SAP internalization in HeLa cells was observed by three different microscopy techniques—TEM, confocal laser scanning microscopy (CLSM) and transmission X‐ray microscopy (TXM)—and all of them have confirmed the effective intracellular delivery of AuNps by SAP.
Expanding the Scope of Protein Trans‐Splicing to Fragment Ligation of an Integral Membrane Protein: Towards Modulation of Porin‐Based Ion Channels by Chemical Modification
Authors: Brenzel Steffen , Cebi Menekse , Reiß Philipp , Koert Ulrich , Mootz Henning D. 
Published: March 2009

AbstractIt's raining, it's porin: Fragment ligation of OmpF ion channels was achieved by using the split Psp‐GBD Pol intein; this allowed reconstitution of active trimeric porin. In combination with cysteine modification at an internal position, the porin's conductance properties were altered.magnified image
Generating CuII–Oxyl/CuIII–Oxo Species from CuI–α‐Ketocarboxylate Complexes and O2: In Silico Studies on Ligand Effects and CH‐Activation Reactivity
Authors: Huber Stefan M. , Ertem Mehmed Z. , Aquilante Francesco , Gagliardi Laura , Tolman William B. , Cramer Christopher J. 
Published: March 2009

AbstractTheoretically speaking: The mechanistic details associated with the generation and reaction of [CuO]+ species from CuI–α‐ketocarboxylate complexes, especially with respect to modifications of the ligand supporting the copper center, were investigated (see scheme). Theoretical models were used to characterize the electronic structures of different [CuO]+ species and their reactivity in CH activation and O‐atom transfer reactions.magnified imageA mechanism for the oxygenation of CuI complexes with α‐ketocarboxylate ligands that is based on a combination of density functional theory and multireference second‐order perturbation theory (CASSCF/CASPT2) calculations is elaborated. The reaction proceeds in a manner largely analogous to those of similar FeII–α‐ketocarboxylate systems, that is, by initial attack of a coordinated oxygen molecule on a ketocarboxylate ligand with concomitant decarboxylation. Subsequently, two reactive intermediates may be generated, a Cu–peracid structure and a [CuO]+ species, both of which are capable of oxidizing a phenyl ring component of the supporting ligand. Hydroxylation by the [CuO]+ species is predicted to proceed with a smaller activation free energy. The effects of electronic and steric variations on the oxygenation mechanisms were studied by introducing substituents at several positions of the ligand backbone and by investigating various N‐donor ligands. In general, more electron donation by the N‐donor ligand leads to increased stabilization of the more CuII/CuIII‐like intermediates (oxygen adducts and [CuO]+ species) relative to the more CuI‐like peracid intermediate. For all ligands investigated, the [CuO]+ intermediates are best described as CuIIO⋅− species with triplet ground states. The reactivity of these compounds in CH abstraction reactions decreases with more electron‐donating N‐donor ligands, which also increase the CuO bond strength, although the CuO bond is generally predicted to be rather weak (with a bond order of about 0.5). A comparison of several methods to obtain singlet energies for the reaction intermediates indicates that multireference second‐order perturbation theory is likely more accurate for the initial oxygen adducts, but not necessarily for subsequent reaction intermediates.
Modulating Large‐Area Self‐Assembly at the Solid–Liquid Interface by pH‐Mediated Conformational Switching
Authors: Piot Luc , Meudtner Robert M. , El Malah Tamer , Hecht Stefan , Samorì Paolo 
Published: March 2009

AbstractDynamic surfaces: The conformational transition of 2,6‐bis(1‐aryl‐1,2,3‐triazol‐4‐yl)pyridine (BTP) derivatives, triggered by a change in pH, has been observed with a sub‐nm resolution by STM at the solid–liquid interface. Upon addition of trifluoroacetic acid two different BTP molecules, each forming a highly ordered physisorbed monolayer, underwent significant conformational changes from their “rosette” to their “tetragon” forms, as reflected in dramatically altered 2D self‐assembly over large areas extending over hundreds of nanometers (see graphic).magnified image
Influence of Counteranion on the Chiral Supramolecular Assembly of Alkynylplatinum(II) Terpyridyl Metallogels That Are Stabilised by Pt⋅⋅⋅Pt and π–π Interactions
Authors: Tam Anthony Yiu‐Yan , Wong Keith Man‐Chung , Yam Vivian Wing‐Wah 
Published: March 2009

AbstractHelical superstructures: A series of luminescent chiral alkynylplatinum(II)–terpyridyl complexes has been successfully synthesised and shown to be capable of forming metallogels that show helical fibrous nanostructures. The chiral supramolecular structure and the spectroscopic properties are found to depend on the extent of aggregation through Pt⋅⋅⋅Pt and π–π interactions in various counteranions, as revealed by UV/Vis, circular dichroism (CD), and luminescence studies (see picture).magnified image
Theoretical analysis of absorption of chlorine in aqueous slurries of calcium hydroxide: Desorption of hypochlorous acid gas
Authors: Mogal M. M. B. , Yadav G. D. 
Published: March 2009

AbstractA theory has been developed for the absorption of chlorine in aqueous slurries of calcium hydroxide accompanied by a two‐step instantaneous reaction and desorption and simulation is carried out to study the effects of various parameters. The rates of absorption of chlorine and desorption of HOC1 from the aqueous slurry are enhanced when fine particles are present in two diffusion film regions on the liquid side. It is concluded that intensification in the rates of absorption of chlorine and rates of desorption can be realized by using high loading of smaller particle size. An optimum kL must be used to enhance rates of Cl2 absorption and HOG desorption in order to permit the formation of two reaction planes in the diffusion film. Rates can be intensified by an order of magnitude by the proper selection of operating conditions.
Evaluation of the flow rate of an electro‐rheological fluid (corn starch‐kerosene) flowing through a narrow channel formed by a pair of electrodes
Authors: Kobayashi Kazumasa , Okamura Keiji , Sakai Takeshi , Sato Masayuki 
Published: March 2009

AbstractThe flow rate of a com starch‐kerosene ERF through a narrow channel formed by a pair of electrodes has been measured over a range of electric fields between 0 and 2.8 kV/mm. The effect of the entrance shape and various electrode configurations on the flow rate of the ERF has been examined. The relationship between the flow rate and applied voltage is theoretically analysed on the assumption that the ERF is a Bingham fluid and compared with the observed values. It has been illustrated that the theoretically derived relationship is in good agreement with the observed values if a correction term or adjustable parameters are incorporated.
Catalytic methane coupling under periodic operation
Authors: Mortazavi Y. , Hudgins R. R. , Silveston P. L. 
Published: March 2009

AbstractComposition modulation strategies for improving selectivity to the C2 products in the oxidative coupling of methane were investigated experimentally with Li2O/MgO and CeO/Li2O/MgO catalysts at about 100 kPa pressure and 750°C. Strategies used were 1) “methane cycling” between mixtures with different concentrations of CH4, 2) “oxygen cycling” between mixtures with different concentrations of oxygen, 3) bang‐bang cycling (air‐CH4), and 4) flushing the catalyst with an inert between exposures to reactants.Experimental C2 yields and ethylene to total C2 ratios showed that composition forcing is better with the Ce/Li/MgO catalyst. Methane cycling proved to be the best strategy explored.
Study of unsteady‐state catalytic oxidation of sulfur dioxide by periodic flow reversal
Authors: Huixiong Wu , Shuzeng Zhang , Chengyue Li 
Published: March 2009

AbstractA systematic study of catalytic oxidation of sulfur dioxide in a fixed bed reactor operated in flow reversal mode was made. A heterogeneous transient model of the reactor was developed. The global rate equations and the heat transfer parameter correlation were obtained, based on a series of previous experiments. The experiments of unsteady‐state oxidation of low concentration SO2 were conducted in a bench‐scale fixed bed reactor, packed with a domestic commercial catalyst. The model can successfully predict the transient concentration and temperature profiles when a correction factor is introduced to the global rate equations.
Modelling and experimental studies on unsteady‐state SO2 converters
Authors: Xiao Wen‐De , Yuan Wei‐Kang 
Published: March 2009

AbstractThis paper deals with experimentation of the unsteady‐state fixed‐bed reactor with flow reversal for SO2 conversion. A laboratory reactor with compensatory heating coils has been set up, resulting in 96–99% conversion for SO2 = 2.62–9.52 vol%, and u = 0.2 m/s. The results were from agreement with simulation of a really adiabatic unsteady‐state reactor, but agreed well with modelling by considering the radial heat transfer. A three‐stage pilot‐scale converter has also been run with the M‐typed temperature profile produced by heat loss from the chamber between stages. Good agreement was achieved with modelling by taking into account this feature. The results show that, while the adiabatic requirement is difficult to fulfill in the well‐accepted experimental reactors, simulation and modelling are powerful means for compensation.
Modeling of grain drying in continuous cross‐flow sliding bed dryers
Authors: Mayta S. Miguel A. , Massarani Giulio , Pinto José Carlos 
Published: March 2009

AbstractTwo mathematical models were developed in order to describe grain drying in continuous cross‐flow sliding bed dryers: a purely convective model and a diffusive model. It is shown both theoretically and experimentally that diffusion is not fundamental for the proper description of corn and soybean in these dryers at usual operation conditions, in spite of the widespread usage of diffusion‐like models. Particularly, the purely convective model may be easily implemented and used to optimize drying operation at plant site.
Metabolic responses of plant cell culture to hydrodynamic stress
Authors: Takeda Toshiya , Kitagawa Takanori , Takeuchi Yoshikuni , Seki Minoru , Furusaki Shintaro 
Published: March 2009

AbstractThe metabolic responses of eucalyptus and safflower cells to hydrodynamic stress in a 550‐cm3 stirred tank reactor were investigated. At 0.5 — 2.3 m2/s3 of energy dissipation rate, the decreases in respiration rate and ATP content were larger than the decrease in the membrane integrity. Intracellular NAD(P)H was decreased and cytosolic calcium content was increased by agitation. EGTA, verapamil and W‐7 suppressed the decrease in NAD(P)H. These results suggest that the cytosolic calcium, as a second messenger, mediate the signal of the hydrodynamic stress into the metabolism which induces the decrease in respiration rate. Furthermore, a decrease in the filamentous actin content due to agitation was observed.
Newtonian power curve and drop size distributions for vibromixers
Authors: Lo Mei Y. A. , Gierczycki Andrej T. , Titchener‐Hooker Nigel J. , Shamlou Parviz Ayazi 
Published: March 2009

AbstractPower input data are presented for a twin flat disk up‐and‐down moving (vibromixer) impeller operating in a small vessel with a range of Newtonian liquids. Vibromixer power number and Reynolds number are defined and are used to establish the Newtonian power curve for this type of mixer. Drop size distributions are presented for xylene‐in‐water dispersions under turbulent flow conditions in the vibromixer and are shown to vary with the maximum velocity of the disk (2πAf). The Sauter mean drop diameter of the distribution is related to the vibromixer Weber number, (We =ρ(2πAf)2D/σ), by an equation of the type d32/D = C (We)−3/5 with the coefficient C = 0.37.
Pumping, spraying, and mixing of fluids by electric fields
Authors: Tsouris Costas , Shin Won‐Tae , Yiacoumi Sotira 
Published: March 2009

AbstractThe mechanism of electrostatic spraying of insulating fluids, such as air or organic solvents, into relatively conductive fluids, such as water, is investigated in this work. Experiments with air sprayed into water through an electrified capillary showed that the pressure inside the capillary increases, reaches a maximum, and then decreases as the applied voltage is increased. The initial pressure increase is due to the electric stress on the fluid interface, while the decrease is due to the Coulombic electrohydrodynamic flow generated near the end of the capillary. It is shown that electric fields can cause simultaneous pumping, spraying, and mixing of fluids. This phenomenon is demonstrated for air and kerosene in water.
Etude de l'influence du mode d'anodisation sur la cinétique de croissance des films d'alumine en milieu acide sulfurique
Authors: Azzouz Noureddine , Belmokre Kamel , Taallah Habib , Pagetti Jacques 
Published: March 2009

AbstractThe kinetics of growth of Al2O3 oxide films made by anode oxidation of ALuminium 1050A with two anodization techniques has been investigatedan compared. The first technique is the classical method based on continuous tension during the complete electrlysis duration, and the second one is the modern method ofpulsed tensions, whcih consists of periodically imposing to the material two anodc tensions E1 and E2 (E1 > E2) during time T1 and T2 until the end on anodization. We have shown that the second technique allows the fabrication of films more rapidly for the same electrolysis duraton. Energy and electrolysis time are saved, making it attractive from an economical viewpoint. This advantage arises from the positive effect of excess heat disiption gathered during the imposition of tension, E1, when E2 is imposed thereafter (recovery effect). The logging of in situ transient responses in the case of pulsed anodization is a significant asset to explain the growth film kinetics obtained with this method.
Rheological properties of aqueous α A12O3 suspensions: Influence of dispersant concentration
Authors: Zupančič Andreja , Lapasin Romano , Kristoffersson Annika 
Published: March 2009

AbstractThe effects of concentration of polyacrylic acid as a dispersant on rheological properties of aqueous alumina suspensions have been investigated under steady and oscillatory shear conditions. At solid volume fractions between 0.45 and 0.6, a high degree of particle stabilization is achieved when 0.2 wt% of polyacrylic acid is added. At lower dispersant concentrations, suspensions exhibit pronounced irreversible thixotropic behaviour, whereas at higher dispersant concentrations, time dependent effects on the flow properties are not detectable. When the saturation adsorption limit of the polyelectrolyte on Al2O3 is reached, further addition of the dispersant appreciably changes the flow behaviour, as well as the viscoelastic response of investigated suspensions. The data under steady shear are described by application of the generalized Casson model, and for the analysis of viscoelastic data the generalized Maxwell model is used.
Effects of Thymoquinone–Fatty Acid Conjugates on Cancer Cells
Authors: Breyer Sandra , Effenberger Katharina , Schobert Rainer 
Published: March 2009

AbstractMore than the sum of its parts: The seeds of Nigella sativa have been a traditional herbal remedy for ailments such as asthma, diarrhea, and cancer. Their essential oil is rich in polyunsaturated fatty acids and thymoquinone. By linking them covalently, a tremendous boost in anticancer activity can be achieved in resistant tumor cells.magnified image4‐Acylhydrazones and 6‐alkyl derivatives of thymoquinone (TQ) were tested for growth inhibition of human HL‐60 leukemia, 518A2 melanoma, KB‐V1/Vbl cervix, and MCF‐7/Topo breast carcinoma cells. Unsaturated side chains conferred greater activities than equally long saturated chains. The number of CC bonds was less decisive than chain length. The 6‐hencosahexaenyl conjugate 3 e was most active in all resistant tumor cells, with IC50 (72 h) values as low as 30 nM in MCF‐7/Topo cells. The conjugates are likely to operate by mechanisms different from that of TQ. For instance, 3 e induced distinct caspase‐independent apoptosis in HL‐60 and 518A2 cells concomitant with a loss of mitochondrial membrane potential and a subsequent rise in the levels of reactive oxygen species.
Synthesis and Biological Evaluation of New Geiparvarin Derivatives
Authors: Chimichi Stefano , Boccalini Marco , Salvador Alessia , Dall'Acqua Francesco , Basso Giuseppe , Viola Giampietro 
Published: March 2009

AbstractNew geiparvarin derivatives modified at the alkenyloxy bridge, where the 3′‐methyl group was replaced by a hydrogen atom, were synthesized and evaluated against a panel of human tumor cell lines in vitro. Compounds (R)‐4 and (R)‐5 show greater inhibitory activity toward cell growth than the parent geiparvarin.magnified imageNew geiparvarin derivatives modified at the unsaturated alkenyloxy bridge, where a hydrogen atom replaces the 3′‐methyl group, were synthesized and evaluated against a panel of human tumor cell lines in vitro. These compounds demonstrated an increase in growth inhibitory activity relative to the parent compound, geiparvarin. The activity increased even further in the series of demethylated compounds, with the introduction of a methyl group at the 1′‐position of the alkenyloxy chain. In contrast, a remarkable decrease in activity was observed with the introduction of a methyl group at the 2′‐position. Interestingly, the new derivatives fully inhibited the growth of drug‐resistant cell lines, suggesting that they are not subject to pump‐mediated drug efflux. On the basis of their cytotoxic profiles, the most active compounds (R)‐4 and (R)‐5 were selected for further biological evaluation in comparison with the lead compound. The new derivatives strongly induce apoptosis in a promyelocytic leukemia cell line (HL‐60) mediated by depolarization of mitochondrial transmembrane potential and mitochondrial production of reactive oxygen species (ROS).
Analysis of Non‐Covalent Bioconjugation of Colloidal Nanoparticles by Means of Atomic Force Microscopy and Data Clustering
Authors: Irrgang Jessica , Ksienczyk Jacqueline , Lapiene Vidmantas , Niemeyer Christof M. 
Published: March 2009

AbstractAFM topography data of non‐covalently assembled biomolecule–nanoparticle hybrids is examined by statistical cluster analysis (see figure). As exemplified for fluorescent‐protein‐modified quantum dots and DNA/protein‐conjugated gold nanoparticles, this analytical approach provides insights into the formation of bioconjugate populations.magnified imageNon‐covalent modification of nanoparticles with biomolecules is frequently applied in the generation of hybrid nanomaterials. Herein, we report on the analysis of non‐covalently assembled hybrid nanoparticles on surfaces, using AFM measurements and examination of the resulting topography data by means of statistical cluster analysis. Two different model systems are investigated. On the one hand, we apply the combined AFM–cluster analysis to CdSe/ZnS core/shell quantum dots, bioconjugated with varying amounts of the hexahistidine‐tagged enhanced yellow fluorescent protein (EYFP). On the other hand, gold nanoparticles modified with single‐stranded DNA oligonucleotides were further functionalized by Watson–Crick base pairing, using complementary DNA oligonucleotides or covalent conjugates of DNA and streptavidin or EYFP. The results clearly indicate that cluster analysis of AFM data allows for the identification of sub‐populations in complex reaction mixtures. Therefore, this analytical approach is useful to elucidate bioconjugate species, formed in the course of non‐covalent synthesis of nanoparticle–biomolecule hybrid systems.
Mediation by any other name would smell as sweet—or would it? The struggle to define mediation and its various approaches
Authors: Charkoudian Lorig , Ritis Cristian De , Buck Ramona , Wilson Carrie L. 
Published: March 2009

AbstractThis article reports on two studies. The analysis of the first study, a survey of 250 mediators, finds four distinct groups of mediator “clusters,” based on self‐reported strategies. These four clusters are described in detail and mediators' self‐defined labels are then correlated with the four clusters. There is little consistency between the labels mediators give their approach and the cluster into which they actually fall in this survey. The analysis of the second study, which involved observation and coding of actual mediations, finds that those mediators who were observed to use any directive strategies tended to use mostly directive strategies and those mediators who were observed to use any elicitive strategies tended to use mostly elicitive strategies throughout the observed mediation case. This challenges the notion that mediators may use both directive and elicitive strategies together in the same mediation.
Building trust with parties: Are mediators overdoing it?
Authors: Stimec Arnaud , Poitras Jean 
Published: March 2009

AbstractTrust is a key factor in the dynamics of any attempt to settle a conflict. A mediator may be the needed link between the parties, as long as they trust their mediator. But how far should mediators go to win parties' trust? On the basis of questionnaires filled out by participants in employer‐employee mediation, we arrive at a conclusion that differs from the prevailing wisdom. There is a threshold point rather than a linear relationship between the level of trust in the mediator and the degree of conflict resolution. Once the threshold has been reached, additional trust does not necessarily result in a higher level of conflict resolution. Possible explanations are set out and practical implications are discussed.
Shadows, conflict, and the mediator
Authors: McGuigan Richard 
Published: March 2009

AbstractThis article discusses a theory of mediator psychological growth specifically focusing on Carl Jung's concept (1954) of the Shadow. The nature and development of the Shadow are outlined, with particular attention to the mechanism of projection, applied to the perspectives of both the individual and the group. The importance of the mediator uncovering and owning his or her Shadow material is underscored, along with some strategies for doing so. This article responds to Bowling and Hoffman's third stage of mediator development (2003), where the mediator is committed to gaining greater awareness of how personal qualities influence the mediation process.