bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organosoluble Polyelectrolyte‐Surfactant Complexes
Authors: Kudaibergenov Sarkyt E. , Sadakbayeva Zhansaya K. , Tatykhanova Gulnur S. , Medard Nicolas , Seitov Arman S. , Abdullin Khabib A. 
Published: August 2012

AbstractOrganosoluble polyelectrolyte‐surfactant complexes (PSCs) based on cationic polymer – JR‐400 and anionic surfactant – sodium salt of dodecylbenzenesulfonate (SDDBS) were isolated as a precipitate from polyelectrolyte/surfactant aqueous mixture. The reduced viscosity of JR‐400/SDDBS in ethanol showed polyelectrolyte anomaly that was suppressed upon addition of 0.05N and 0.1N KBr. Light scattering measurements of JR‐400/SDDBS in ethanol showed 4 peaks belonging to non‐aggregated and aggregated polycomplex particles. The elemental composition and morphology of thin layers of polyelectrolyte‐surfactant complexes deposited on SiO2surface were evaluated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The height of PSC aggregates evaluated using AFM and Surface Enhanced Ellipsometry Contrast (SEEC) microscopy data is in good agreement and range within 10–50 nm. The XRD analysis revealed that PSCs have amorphous structure with a broad halo near 20 °. The contact angle measurements were used to demonstrate the hydrophobization of glass surface after the deposition of PSCs.
Behavior of a Polyion at the Charged Wall of the Same Sign in Presence of Counterions and of a System of two Equal Uncharged Polymer chains. Study by Monte Carlo Method
Authors: Antipina A. Yu. , Antyukhova M. A. , Yurchenko A. A. , Vorontsov‐Velyaminov P. N. 
Published: August 2012

AbstractIn this paper Monte Carlo simulations of two polymer systems are presented. The first system is a single polyion near the plane charged wall of the same sign with presence of counterions. The interest in studying this system is stimulated by experiments on binding of negatively charged DNA deposited on the negatively charged substrate.1 The second system contains two non‐charged polymer chains with attractive or repulsive intrachain interaction and attraction between chains in both cases. Treatment of this system is aimed at further simulation of a system of polyions as the next step. In both cases the continuous and discrete models of chains were considered and Monte Carlo simulation method within Wang–Landau algorithm was used. It allowed to obtain the energy‐distribution functions that in its turn made it possible to calculate various thermal properties of the systems in a wide temperature range: thermodynamic quantities and structural characteristics (root mean‐square radius of gyration, root mean‐square distance between the centers of mass of two polymers).
Syntheses of Silver Nanoparticles in the Matrices of Block and Graft Copolymers and Polymer‐Inorganic Hybrid in Aqueous Solutions
Authors: Fedorchuk Sergey , Zheltonozhskaya Tatyana , Gomza Yuriy , Nessin Stanislav , Kunitskaya Larisa , Demchenko Olga 
Published: August 2012

AbstractIn the present work we have synthesized two‐component block‐ and graft copolymers MOPEO‐b‐PAAm, PAAm‐b‐PEO‐b‐PAAm and PVA‐g‐PAAm comprised methoxypoly(ethylene oxide), poly(ethylene oxide) or poly(vinyl alcohol) and chemically complementary polyacrylamide and also the grafted polymer‐inorganic hybrid SiO2‐g‐PAAm based on monodispersed silica nanoparticles. These copolymers we used as special matrices in the process of borohydride reduction of Ag+ ions. It was established the influence of chemical nature, molecular architecture and concentration of the matrices and the content of silver nitrate on some reaction parameters, size and stability of Ag‐nanoparticles in aqueous solutions.
Mechanochemical Formulation of Coating Iron Oxides Magnetic Nanoparticles with Humics
Authors: Yurishcheva Anna , Dzhardimalieva Gulzhian I. , Pomogailo Svetlana , Pomogailo Anatoly D. , Jorobekova Sharipa , Kydralieva Kamila 
Published: August 2012

AbstractThis paper identifies properties of magnetite nanoparticles when combined with macromolecules of humic substances in a nanocomposite matrix using mechanochemical dispersion technique. This method is described providing an inexpensive production methods for sorbents with the requisite properties for binding heavy metals.
Synthesis and Characterization of Nanosized Pectin‐Based Formulations
Authors: Zakharova Natalia , Kydralieva Kamila , Khudaibergenova Elnura , Gorbunova Nina , Pomogailo Svetlana , Dzhardimalieva Gulzhian I. , Pomogailo Anatoly , Jorobekova Sharipa 
Published: August 2012

AbstractPectin conjugated magnetic nanocomposites were prepared by chemical coprecipitation method in situ. The FTIR, acoustic, Mössbauer spectrometry, XRD measurements confirmed the nanoscaled structure of Fe3O4‐pectin composite. The synthesized magnetite nanoparticles were uniform with an mean size of ∼14–17 nm for low pectin concentration as 10 wt.%.
Synthesis and Characteristics of Acetylenedicarboxylic Acid Salts as Precursors for Obtaining of Nanocomposites
Authors: Shershnev Vitaly A. , Shilov Gennady V. , Dzhardimalieva Gulzhian I. , Pomogailo Anatoly D. , Izydorzak Marta , Leonowicz Marcin 
Published: August 2012

Abstractacetylenedicarboxylic acid salts were used as precursors for further polymerization and thermal degradation to obtain nanocomposites. Monomers and composites structure was investigated with different methods including IR spectroscopy, thermal analysis and electron microscopy.
Bioactive Electroconductive Hydrogels Yield Novel Biotransducers for Glucose
Authors: Kotanen Christian N. , Guiseppi‐Elie Anthony 
Published: August 2012

AbstractA class of bioactive, stimuli‐responsive co‐joined interpenetrating networks of inherently conductive polymers and highly hydrated hydrogels are being developed for implantable biodevice interfaces and for electric field induced release of elutable drugs. A novel microfabricated multidisc electrode array biotransducer intended for trauma management has been coated with poly(HEMA)‐polypyrrole and characterized by cyclic voltammetry and chronoamperometry using ferrocene monocarboxylic acid (FcCOOH) as a probe molecule. Electrodeposition of polypyrrole (700 mV vs. Ag/AgCl) to 100 mC/cm2 onto the hydrogel coated microdisc electrode array resulted in large and unstable background currents relative to uncoated electrodes. Overoxidation of polypyrrole (0–1.2 V vs. Ag/AgCl, 20 cylces, 100 mV/s) eliminates background current. Dose‐response curves with FcCOOH showed that the transducer has good reproducibility with molecules of facile electrochemical properties. Polypyrrole provides interference screening of endogenous interferents in biosensor applications with a 12:1 rejection ratio. GOx was immobilized via electropolymerization of polypyrrole into hydrogel coated MDEA 5037s to yield biotransducers with sensitivity of 0.045 µA mM−1 cm−2. Changes to improve biotransducer sensitivity are proposed.
Polypeptides‐Induced Self‐Aggregation and Tuning of Emission Properties of Luminescent Complexes
Authors: Moriuchi Toshiyuki , Yamada Masahiro , Yoshii Kazuki , Katano Chiaki , Hirao Toshikazu 
Published: August 2012

AbstractThe assembling of anionic [Au(CN)2]− spatially along cationic β‐sheeted poly‐L‐lysine (P(Lys)) through electrostatic and aurophilic bonding interactions was demonstrated to form the luminescent [Au(CN)2]− aggregate, wherein negatively charged [Au(CN)2]− was found to stabilize the β‐sheet structure by suppressing repulsion between the positively charged side chains. Poly‐L‐glutamic acid (P(Glu)) bearing multiple negatively charged side chains was performed to serve as a polymeric spatially aligned scaffold for aggregation of the positively charged platinum(II) complexes [Pt(trpy)CCR](OTf) (trpy = 2,2′,6′,2″‐terpyridine; R = Ph (PtH), C6H4C12H25‐p (PtC12)) through electrostatic interaction, resulting in tunable emission properties. The introduction of the cationic luminescent iridium(III) and ruthenium(II) complexes into P(Glu) as a polymeric scaffold, wherein control of the conformational change of P(Glu) was achieved, was also allowed to induce the tuning of the emission properties and energy transfer in aqueous media.
Macromolecular Complexes Leading to High‐Performance Energy Devices
Authors: Oyaizu Kenichi , Nishide Hiroyuki 
Published: August 2012

AbstractDynamic interactions and electronic processes in macromolecule‐metal complexes established in 1970s provided conceptual basis for the development of a new class of functional polymers. Principles of soft/multiple interaction and multielectron processes have been pursued by exploring the macromolecule‐metal complexes and polyion complexes, which gave rise to more generalized concept of macromolecular complexes. As one of the multiple interaction, reversible binding of O2 in aqueous media and facilitated transport of O2 were first accomplished by macromolecular metal complexes. The related oxygen technologies have led to the development of unprecedented materials to allow oxygen enrichment in cathodes of fuel cells and air batteries. Properties of electric/ionic conduction and electron transfer mediation in macromolecular complexes suggested our avenue toward the “radical batteries” as entirely organic, rare metal‐free, and rechargeable burst power sources. Combination of the photoelectrochemistry of macromolecular complexes and the methods for the precision control of charge separation, transport, and storage in polymers derived from the battery research have inspired design principles of novel photovoltaic polymers useful for organic solar cells. In this paper, recent developments of energy‐related materials originated from the idea of the macromolecular complexes are focused.
Formation of a tunable starch‐based network by in situ incorporation of mercapto groups and a subsequent thiol‐ene click reaction
Authors: Huang Li , Xiao Congming 
Published: August 2012

AbstractA tunable starch‐based hydrogel was prepared by crosslinking unsaturated macromonomers in the presence of H2S. First, well‐defined poly(vinyl alcohol) (PVA) was prepared by alcoholysis of poly(vinyl acetate) obtained by reversible addition‐fragmentation chain transfer (RAFT) polymerization of vinyl acetate. Subsequently, carbon‐carbon double bonds were incorporated onto PVA through esterification with maleic anhydride. Finally, the hydrogel was formed via concurrent electrophilic addition and thiol‐ene reaction between starch maleic half‐ester, unsaturated PVA and H2S using potassium persulfate as initiator at 60 °C. Elemental analysis showed the percentage of sulfur in the gel ranged from 0.86% to 1.73%, depending on the chain length of PVA. The storage modulus, loss modulus and glass transition temperature of the networks varied from 12.7 to 50.9 MPa, from 3.7 to 15.7 MPa and from 57.0 to 71.8 °C, respectively. Both the swelling and release behavior of the gels were also modulated by changing the unsaturated PVA component. © 2012 Society of Chemical Industry
Influence of the Z‐group on the RAFT‐mediated polymerizations in nanoreactors
Authors: Valade David , Jeon Yujung , Kessel Stefanie , Monteiro Michael J. 
Published: August 2012

AbstractIn this work, we showed that the self‐assembly behavior of the macro‐chain transfer agent P(DMA69‐b‐NIPAM60)‐S(CS)SC12H25 [dodecyltrithiocarbonate (DTTC)] was very different to P(DMA68‐b‐NIPAM62)‐S(CS)SC4H9 [butyltrithiocarbonate (BTTC)], resulting in very different water‐based nanoreactor polymerizations. The DTTC diblock formed small aggregates below the lower critical solution temperature (LCST), which increased slightly above the LCST. This is in contrast to the BTTC diblock, in which unimers existed below the LCST and large aggregates of core–shell nanoreactors were present above the LCST. Polymerization of styrene in the DTTC diblock nanoreactors afforded fast rates of polymerization with the production of narrow molecular weight and particle size distributions. We found a direct relationship between the size and the targeted molecular weight; the greater the targeted the molecular weight the greater the particle size. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Aqueous reversible addition‐fragmentation chain transfer dispersion polymerization of thermoresponsive diblock copolymer assemblies: Temperature directed morphology transformations
Authors: Kessel Stefanie , Truong Nghia P. , Jia Zhongfan , Monteiro Michael J. 
Published: August 2012

AbstractIn this work, we demonstrate the formation of various 3D structures formed by a structural reorganization; a process not governed by self‐assembly. First, we packaged well‐defined diblocks, thermoresponsive poly(N‐isopropylacrylamide‐b‐styrene) or P(NIPAM‐b‐STY), into spherical particles made in situ using a reversible addition‐fragmentation chain transfer (RAFT) nanoreactor technique in water to obtain high polymer solids. The resultant spheres reorganized through a temperature stimulus to form equilibrium and kinetically trapped structures; we denote this process as temperature directed morphology transformation (TDMT). Cylinder and vesicle structures, other more unusual loop, buckled sphere and cauliflower (via ultrasound) structures were observed below the lower critical solution temperature (LCST) of PNIPAM. These structures were produced efficiently, rapidly, reproducibly at high polymer solids and can be stored for years in solution or be freeze‐dried and rehydrated without a change in structure, which becomes important in biological applications. We generated the first phase diagram for the TDMT changes of thermoresponsive diblock micelles in concentrated solutions (> 7% polymer solids) produced from narrow molecular weight diblock copolymers (PDI ∼ 1.1). The sphere/cylinder and cylinder/vesicle transition in the phase diagram were surprisingly found to be predominantly dictated by the length of the hydrophilic block, poly(N‐isopropylacrylamide). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Protective encapsulation of acid‐sensitive catalysts using polyethylene ligands
Authors: Suriboot Jakkrit , Hobbs Christopher E. , Yang Yun‐Chin , Bergbreiter David E. 
Published: August 2012

AbstractThe stability of polyethylene oligomer (PEOlig)‐entrapped salen‐metal complexes toward acidolysis is described. These complexes dissolve in hot toluene and precipitate as hydrophobic powders. The salen species in these precipitates or in precipitates of admixtures of oligomeric complexes and unfunctionalized polyethylene are stable to acid when suspended in acidic methanol for 24 h at 25°C. The lack of metal leaching due to acid‐promoted demetalation was determined using both colorimetric and ICP‐MS analyses. The ICP‐MS results showed the amount of metal loss for PEOlig‐salen‐metal complexes was 0.27%, 0.45%, and 0.79% for half‐salen Cr(III), salen Cr(III), and salen Mn(III) complexes, respectively. These results were in contrast to the reported behavior of low molecular weight salen metal complexes and to results seen with a salen complex bound to divinylbenzene (DVB) crosslinked polystyrene which demetalates under acidic conditions at room temperature. Salen complexes formed with PEOlig complexes also demetalate when the PEOlig‐bound species are in solution at elevated temperature and exposed to acid. These results show that as solids oligomeric polyethylene ligands even without added PE can serve as a protective encapsulating matrix for the solid forms of polymer‐supported catalysts. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
In Situ TEM Electromechanical Testing of Nanowires and Nanotubes
Authors: Espinosa Horacio D. , Bernal Rodrigo A. , Filleter Tobin 
Published: August 2012

AbstractThe emergence of one‐dimensional nanostructures as fundamental constituents of advanced materials and next‐generation electronic and electromechanical devices has increased the need for their atomic‐scale characterization. Given its spatial and temporal resolution, coupled with analytical capabilities, transmission electron microscopy (TEM) has been the technique of choice in performing atomic structure and defect characterization. A number of approaches have been recently developed to combine these capabilities with in‐situ mechanical deformation and electrical characterization in the emerging field of in‐situ TEM electromechanical testing. This has enabled researchers to establish unambiguous synthesis‐structure‐property relations for one‐dimensional nanostructures. In this article, the development and latest advances of several in‐situ TEM techniques to carry out mechanical and electromechanical testing of nanowires and nanotubes are reviewed. Through discussion of specific examples, it is shown how the merging of several microsystems and TEM has led to significant insights into the behavior of nanowires and nanotubes, underscoring the significant role in‐situ techniques play in the development of novel nanoscale systems and materials.
Vapor‐Phase Hydrothermal Transformation of HTiOF3 Intermediates into {001} Faceted Anatase Single‐Crystalline Nanosheets
Authors: Liu Porun , Wang Yun , Zhang Haimin , An Taicheng , Yang Huagui , Tang Zhiyong , Cai Weiping , Zhao Huijun 
Published: August 2012

AbstractFor the first time, a facile, one‐pot hydrofluoric acid vapor‐phase hydrothermal (HF‐VPH) method is demonstrated to directly grow single‐crystalline anatase TiO2 nanosheets with 98.2% of exposed {001} faceted surfaces on the Ti substrate via a distinctive two‐stage formation mechanism. The first stage produces a new intermediate crystal (orthorhombic HTiOF3) that is transformed into anatase TiO2 nanosheets during the second stage. The findings reveal that the HF‐VPH reaction environment is unique and differs remarkably from that of liquid‐phase hydrothermal processes. The uniqueness of the HF‐VPH conditions can be readily used to effectively control the nanostructure growth.
Human Liver Stem Cell-Derived Microvesicles Inhibit Hepatoma Growth in SCID Mice by Delivering Antitumor MicroRNAs
Authors: Fonsato Valentina , Collino Federica , Herrera Maria Beatriz , Cavallari Claudia , Deregibus Maria Chiara , Cisterna Barbara , Bruno Stefania , Romagnoli Renato , Salizzoni Mauro , Tetta Ciro , Camussi Giovanni 
Published: August 2012

Abstract
Microvesicles (MVs) play a pivotal role in cell-to-cell communication. Recent studies demonstrated that MVs may transfer genetic information between cells. Here, we show that MVs derived from human adult liver stem cells (HLSC) may reprogram in vitro HepG2 hepatoma and primary hepatocellular carcinoma cells by inhibiting their growth and survival. In vivo intratumor administration of MVs induced regression of ectopic tumors developed in SCID mice. We suggest that the mechanism of action is related to the delivery of microRNAs (miRNAs) from HLSC-derived MVs (MV-HLSC) to tumor cells on the basis of the following evidence: (a) the rapid, CD29-mediated internalization of MV-HLSC in HepG2 and the inhibition of tumor cell growth after MV uptake; (b) the transfer by MV-HLSC of miRNAs with potential antitumor activity that was downregulated in HepG2 cells with respect to normal hepatocytes; (c) the abrogation of the MV-HLSC antitumor effect after MV pretreatment with RNase or generation of MVs depleted of miRNAs; (d) the relevance of selected miRNAs was proven by transfecting HepG2 with miRNA mimics. The antitumor effect of MV-HLSC was also observed in tumors other than liver such as lymphoblastoma and glioblastoma. These results suggest that the delivery of selected miRNAs by MVs derived from stem cells may inhibit tumor growth and stimulate apoptosis.
Risk Factor of Surgical Site Infection After Pancreaticoduodenectomy
Authors: Sugiura Teiichi , Uesaka Katsuhiko , Ohmagari Norio , Kanemoto Hideyuki , Mizuno Takashi 
Published: August 2012

AbstractBackgroundAlthough surgical site infection (SSI) following pancreaticoduodenectomy is a common complication, the risk factors remain unclear.Patients and methodsA retrospective study of 408 consecutive patients undergoing pancreaticoduodenectomy was conducted and the risk factors for SSI were assessed. The bacterial composition was also analyzed.ResultsSixty‐one patients developed incisional SSI, and 195 developed organ/space SSI. A multivariate analysis identified that length of operation >480 min (odds ratio [OR] 3.22), main pancreatic duct (MPD) ≤3 mm (OR 2.18), and abdominal wall thickness >10 mm (OR 2.16) were significant risk factors for incisional SSI. The development of pancreatic fistula (OR 7.56), use of semi‐closed drainage system (OR 3.68), body mass index >23.5 kg/m2 (OR 3.04), MPD ≤3 mm (OR 2.21), and length of operation >480 min (OR 1.78) were significantly associated with organ/space SSI. Bacterial isolation at the SSI foci revealed that gut‐derived micro‐organisms were the predominant bacterial species.ConclusionsThe presence of pancreatic fistula was the strongest risk factor for organ/space SSI. Efforts to reduce the development of pancreatic fistulas, to decrease length of operation, and to use a closed drainage system would decrease the incidence of SSI following pancreaticoduodenectomy. If SSI that requires antibacterial treatment occurs, then the treatment should target enterobacteria.
Effects of two different instructional formats on scores and reliability of a
script concordance test
Authors: Van den Broek W. E. Sjoukje , Van Asperen Marianne V. , Ten Cate Olle Th. J. , Custers Eug`ene , Valk Gerlof D. 
Published: August 2012

The script concordance test (SCT) is designed to assess clinical reasoning by
adapting the likelihood of a case diagnosis, based on provided new information. In the
standard instructions students are asked to exclude alternative diagnoses they have in
mind when answering the questions, but it might be more authentic to include these.
Fifty-nine final-year medical students completed an SCT. Twenty-nine were asked to take
their differential diagnosis into account (adapted instructions). Thirty students were
asked not to consider other diagnoses (standard instructions). All participants were
asked to indicate for each question whether they were confused answering it with the
given instructions (‘confusion indication’). Mean score of the test with the adapted
instructions was 81.5 (SD 3.8) and of the test with the standard instructions 82.9 (SD
5.0) (p = 0.220). Cronbach’s alpha was 0.39 for the adapted instructions and 0.66 for
the standard instructions. The mean number of confusion indications was 4.2 (SD 4.4) per
student for the adapted instructions and 16.7 (SD 28.5) for the standard instructions
(p = 0.139). Our attempt to improve SCTs reliability by modifying the instructions did
not lead to a higher alpha; therefore we do not recommend this change in the
instructional format.
Lift force reduction due to body image of vortex for a hovering flight model
Authors: Wang X. X. , Wu Z. N. 
Published: August 2012

AbstractThe effect of the body on the lift force in hovering flight is studied here by including the effect of image vortex rings (IVRs) in the inviscid vortex ring model proposed by Rayner (J. Fluid Mech., vol. 91, 1979, pp. 697–730) and used by Wang & Wu (J. Fluid Mech., vol. 654, 2010, pp. 453–472) to study lift force due to wakes. The body is treated simply as an equivalent sphere following the data of Ellington (Phil. Trans. R. Soc. Lond.B, vol. 305, 1984a, pp. 17–40). It is shown that the body image reduces the lift by inducing a further downwash near the wing tip and an additional contraction to the real vortex rings (RVRs). The amount of force reduction due to body image is found to grow cubically with relative body size, defined by the equivalent radius relative to the wing span, and approximately linearly with the feathering parameter. ForApisandBombuswith large relative body size and large feathering parameter, the body images reduce lift by an amount near 8 % according to the present simplified analysis.