bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Hydrogels from Polyallylamine with Carbon Dioxide as Gellant: Development of Reversible CO2 Absorbent
Authors: Nagai Daisuke , Suzuki Akinori , Kuribayashi Takaya
Published: December 2010

Hydrogels were successfully synthesized utilizing CO2 as a gellant. A cross‐linking reaction of polyallylamine (PAA) with CO2 in the presence of 1,8‐Diazabicyclo[5,4,0]‐undec‐7‐ene (DBU) provided hydrogels bearing urea cross‐linking points and residual amino groups in the side chains. The obtained hydrogels absorbed CO2 at 25 °C and gave a maximum absorption four times larger than that of PAA aqueous solution and 2.8 times larger than that of the most commonly used absorbent, monoethanolamine. The PAA hydrogels desorbed the absorbed CO2 completely under a N2 atmosphere at 120 °C, and could be repeatedly recycled without loss of efficiency, indicating their potential application as recyclable CO2 absorption materials.

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Solubility and Aggregation Behavior of Dendronized Poly(p‐Benzamide)s
Authors: Storz Christof , Schulze Maren , Kilbinger Andreas F. M.
Published: December 2010

A series of Fréchet dendronized poly(p‐benzamide)s have been synthesized. To attach the dendron‐functionalities to the poly(p‐benzamide) backbone, a propargyl side chain was introduced to p‐aminobenzoic acid. Then, copper catalyzed azide‐alkyne cycloaddition was used to click a first generation (G1), respectively, a second generation (G2) Fréchet‐dendron azide onto the amino acid monomer. The resulting amino acids were polymerized using triphenylphosphite to obtain a poorly organo‐soluble G1‐dendronized polymer and a non‐aggregating G2‐dendronized polymer showing good organo‐solubility. Furthermore, a strictly alternating non‐aggregating G1‐TEG‐dendronized polymer with good organo‐solubility was synthesized. The aggregation behavior of these polymers was investigated by dynamic light scattering.

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Positive‐/Negative‐, Erasable‐/Immobilized‐, Mono‐/Multi‐Color Fluorescence Image Patterning of Molecular‐Scale Porous Polymer Film via a Microcontact Printing Method Using Various Chemical Inks
Authors: Park Hyosang , Jeong Heejun , Lee Wang‐Eun , Yoon Keun‐byoung , Oh Chang‐Jin , Kwak Giseop
Published: December 2010

Fluorescent image patterns of a substituted acetylene polymer film with a large FFV were successfully obtained by a µCP method using several kinds of chemical ink compounds. PO and SCA generated positive‐type fluorescent image patterns. On the other hand, an ethanolic solution of DNT generated a negative‐type fluorescent image pattern due to a significant quenching effect. An NMP solution of NR gave a two‐color image pattern due to an intermolecular energy transfer from PTMSDPA to NR.

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Polyaniline Microtubes with a Hexagonal Cross‐Section and pH‐Sensitive Fluorescence Properties
Authors: Liu Zhaoyuan , Zhu Ying , Wang Liang , Ding Chunmei , Wang Nü , Wan Meixiang , Jiang Lei
Published: December 2010

Polyaniline (PANI) microtubes with a hexagonal cross‐section are successfully synthesized by a self‐assembly process in the presence of 8‐hydroxyquinoline‐5‐sulfonic acid (HQS) as a dopant and FeCl3 as an oxidant. The wall thickness of the PANI/HQS microtubes can be adjusted by the content of the oxidant. It is proposed that the aniline/HQS salts serve as a hard template for the formation of the hexagonal‐cross‐section microtubes. Moreover, PANI/HQS microtubes combined with ZnSO4 show pH‐dependent fluorescence. PANI hexagonal‐cross‐section microtubes combined with a pH‐sensitive fluorescence may promise potential applications in fields such as chemical sensors and confined reaction vessels.

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Precision Polymers—Modern Tools to Understand and Program Macromolecular Interactions
Authors: Börner Hans G.
Published: December 2010

AB‐block copolymers composed of a common synthetic polymer part and a monodisperse, monomer sequence‐defined segment are considered belonging to the class of “Precision Polymers.” This overview summarizes the possibilities that arise from those precisely adjustable, functional polymers for materials science applications. The freely programmable monomer sequence of the discrete peptide segment allows adjusting properties such as interaction capabilities. This can be exploited to (i) specifically solubilize and transport low molecular weight drugs, (ii) to pack DNA, (iii) to direct crystallization, or (iv) to modulate adhesion behavior of cells on material surfaces. As evident from proteins, the room to improve the precision of synthetic macromolecules will offer plenty of opportunities.

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Fully Aromatic Block Copolymers for Fuel Cell Membranes with Densely Sulfonated Nanophase Domains
Authors: Takamuku Shogo , Jannasch Patric
Published: December 2010

Two multiblock copoly(arylene ether sulfone)s with similar block lengths and ion exchange capacities (IECs) were prepared by a coupling reaction between a non‐sulfonated precursor block and a highly sulfonated precursor block containing either fully disulfonated diarylsulfone or fully tetrasulfonated tetraaryldisulfone segments. The latter two precursor blocks were sulfonated via lithiation‐sulfination reactions whereby the sulfonic acid groups were exclusively placed in ortho positions to the many sulfone bridges, giving these blocks IECs of 4.1 and 4.6 meq·g−1, respectively. Copolymer membranes with IECs of 1.4 meq·g−1 displayed well‐connected hydrophilic nanophase domains and had decomposition temperatures at, or above, 300 °C under air. The copolymer with the tetrasulfonated tetraaryldisulfone segments showed a proton conductivity of 0.13 S·cm−1 at 80 °C under fully humidified conditions, and surpassed that of a perfluorosulfonic acid membrane (NRE212) by a factor of 5 at –20 °C over time.

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Modeling the Dynamics of the Xylene Soluble Fraction (XS) in a Bulk Propylene Polymerization Process
Authors: Machado Fabricio , Pinto José Carlos
Published: December 2010

A model is built to describe the dynamic trajectories of the xylene soluble fraction (XS) in an industrial bulk propylene polymerization process. Emphasis is given to the coupling between the XS dynamics and the reactor liquid bleed policy. It is shown that cocatalyst recirculation can affect the dynamics of the cocatalyst/donor ratio and consequently the dynamics of XS during polymerization. Simulation results indicate that the effect of the reactor liquid bleed operation and of the cocatalyst/donor ratio upon the XS trajectories can be minimized if PI controllers are designed to control the propane concentration and to increase the speed of the cocatalyst/donor transitions. Finally, it is shown that the model is able to reproduce the dynamic XS profile obtained during a large XS transition at plant site.

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Die große Ausnahme: flavinhaltige Blaulichtsensoren
Authors: Pfeifer Anna , Kottke Tilman
Published: December 2010

Im Gegensatz zu allen anderen biologischen Lichtsensoren beruhen die flavinhaltigen nicht auf einer Photoisomerisierung sondern auf Redoxprozessen. Flavinhaltige Blaulichtsensoren steuern unter anderem die innere Uhr und den inneren Kalender vieler Organismen. Auch als Magnetfeldsensor können sie fungieren und sind daher ein Kandidat für die Orientierung von Zugvögeln im Erdmagnetfeld.
Riechen Krebszellen anders?
Authors: Brunner Claudia
Published: December 2010

Die Molekülzusammensetzung im Gasraum über in vitro kultivierten Zellen erlaubt es, Lungenkrebszellen und gesunde Lungenzellen voneinander zu unterscheiden.
Nur gute Zusammenarbeit führt zum Ziel
Authors: Leweke Eva C. , Schmidt Karen
Published: December 2010

Um die Anmeldung gleicher Stoffe unter Reach zu harmonisieren und die Zahl der Tierversuche zu minimieren, gibt es für jeden Stoff ein Forum zum Informationsaustausch. Grundlage einer erfolgreichen Arbeit darin sind Beharrlichkeit, Transparenz und gute IT‐Werkzeuge.
Warum Chemikerinnen gründen
Authors: Osterath Brigitte
Published: December 2010

Existenzgründungen sind in der Chemie seltener als in anderen Branchen. Trotzdem haben sich viele Chemiker zu diesem Schritt entschlossen — auch Frauen. Und sie sind ganz schön erfolgreich.
Protein‐Protein‐Interaktionen webbasiert analysieren
Authors: Krüger Dennis M. , Gohlke Holger
Published: December 2010

Der Drugscore‐PPI‐Webserver ahmt in silico einen Alaninscan nach und sagt so bindungsrelevante Seitenketten in Protein‐Protein‐Komplexen vorher. Damit lässt sich die Signalübertragung in Zellen untersuchen.
Der zerrissene Osten und die gelungene Wiedervereinigung
Authors: Sauer Joachim
Published: December 2010

Man kommt nicht daran vorbei, dass in der DDR die sozialistische Kaderpolitik das Leistungsprinzip bei der Stellenbesetzung, nicht nur von Professorenstellen, systematisch ausgehöhlt hat. Damit wurden viele Menschen aus den Universitäten ausgeschlossen und demotiviert. Der personelle Neuanfang nach der Wende war alternativlos.
Doppelwandige Folien und leichte Autos
Authors: Bulmahn Maren
Published: December 2010

Europäische Spezialitäten und asiatische Massenware, Kunststoffe aus nachwachsenden Rohstoffen und solche, die sich kompostieren oder rezyklieren lassen — die Kunststoffmesse K 2010 bot nahezu jedes Polymer für fast jeden Zweck.
Des Palladiums kleiner Bruder: Neues aus der Nickel‐Katalyse
Authors: Koester Dennis C. , Werz Daniel B.
Published: December 2010

Thema des Nobelpreises für Chemie 2010 waren die palladiumkatalysierten Kupplungsreaktionen. Was aber kann der kleinere Bruder des Palladiums — das Nickel — in der synthetischen organischen Chemie leisten? Befindet sich die Forschung etwa auch auf Nobelpreiskurs?
Unusual functional manifestations of a novel STX11 frameshift mutation in two infants with familial hemophagocytic lymphohistiocytosis type 4 (FHL4)
Authors: Macartney Christine A. , Weitzman Sheila , Wood Stephanie M. , Bansal Deepak , Steele MacGregor , Meeths Marie , Abdelhaleem Mohamed , Bryceson Yenan T.
Published: December 2010

Familial hemophagocytic lymphohistiocytosis (FHL) is typically an autosomal recessive, early‐onset, life‐threatening immune disorder. Loss‐of‐function mutations in STX11 have been found to impair NK cell degranulation and cytotoxicity. Here, we describe two unrelated infants of Punjabi descent presenting with FHL and carrying a novel, homozygous STX11 frameshift mutation [c.867dupG]. Western blot analysis indicated absence of syntaxin‐11. Unexpectedly, degranulation by NK cells from one of the patients was not impaired, although patient NK cells showed mildly and significantly decreased cytotoxicity, respectively. Importantly, these observations imply that STX11 should be sequenced in HLH patients even when impaired NK cell degranulation is not found. Pediatr Blood Cancer 2011;56:654–657. © 2010 Wiley‐Liss, Inc.
Children receiving treatment for cancer and their caregivers: A mixed methods study of their sleep characteristics
Authors: Wright Marilyn
Published: December 2010

Background

Sleep has a significant impact on the daily functioning of children and their parents. The purpose of this study was to describe and gain an understanding of the sleep characteristics of children receiving treatment for cancer and their caregivers using a mixed methods concurrent triangulation design.

Procedure

Data were collected from questionnaires completed by 35 caregivers of children receiving treatment for cancer and compared to similar data from 64 caregivers of healthy children.

Results

There was considerable variability in the sleep characteristics of the children receiving treatment for cancer as reported by their caregivers. However, as a group, the magnitude of their sleep problems, particularly among the adolescents, was significantly greater than that of the comparison group and had the potential to impact negatively on their participation in everyday life. They had poorer sleep efficiency. Many impairments, particularly pain, nightmares, and symptoms associated with steroid administration, impacted their sleep. Their caregivers also experienced an increased prevalence of sleep issues, which impacted their daytime functioning. Suggestions to prevent and treat the sleep issues of children receiving treatment for cancer focused on practicing good sleep habits, ensuring a safe, secure, and comfortable sleep environment, and using non‐pharmaceutical and pharmaceutical interventions to address impairments interfering with sleep. Caregivers noted that it was important to take care of themselves by getting sufficient sleep and accepting help from others.

Conclusions

Sleep issues are prevalent in families of children receiving treatment for cancer and should be assessed routinely and addressed. Pediatr Blood Cancer 2011;56:638–645. © 2010 Wiley‐Liss, Inc.
Initial testing of the hypoxia‐activated prodrug PR‐104 by the pediatric preclinical testing program
Authors: Houghton Peter J. , Lock Richard , Carol Hernan , Morton Christopher L. , Phelps Doris , Gorlick Richard , Kolb E. Anders , Keir Stephen T. , Reynolds C. Patrick , Kang Min H. , Maris John M. , Wozniak Amy W. , Gu Yongchuan , Wilson William R. , Smith Malcolm A.
Published: December 2010

Background

PR‐104 is rapidly hydrolyzed to PR‐104A in vivo, which is activated by reduction to the corresponding 5‐hydroxylamine (PR‐104H) and amine (PR‐104M) to produce DNA interstrand cross‐links. PR‐104 activation can occur via hypoxia‐dependent reductases and also independently of hypoxia by aldo‐keto reductase (AKR) 1C3.

Procedures

PR‐104A was tested against the PPTP in vitro panel (10 nM to 100 µM), and PR‐104 in vivo using a weekly × 6 schedule at its maximum tolerated dose (MTD) of 550 mg/kg. Subsequently PR‐104 was tested at 270 and 110 mg/kg. Pharmacokinetics for PR‐104 and its metabolites were determined, as were levels of AKR1C3 RNA and protein in xenografts.

Results

In vitro, the leukemia models were most sensitive to PR‐104A. In vivo, PR‐104 induced objective responses at its MTD in 21/34 solid tumor models and maintained complete responses against 7/7 acute lymphoblastic leukemia (ALL) models. At 270 mg/kg and lower dose levels, PR‐104 did not induce solid tumor regressions, suggesting a steep dose–response relationship. Pharmacokinetic analysis suggests higher systemic exposures to PR‐104A and its metabolites in mice compared to those achievable in patients. Levels of AKR1C3 protein did not correlate with tumor responsiveness.

Conclusions

As monotherapy, PR‐104 demonstrated a high level of activity against both solid tumor and ALL models at its MTD, but the activity was almost completely lost at half the MTD dose for solid tumors. Pharmacokinetic data at the PR‐104 MTD from human trials suggest that PR‐104 metabolites may not reach the plasma exposures in children that were associated with high‐level preclinical activity. Pediatr Blood Cancer 2011; 57: 443–453. © 2010 Wiley‐Liss, Inc.
Online monitoring and analysis of resin pressure inside composite laminate during zero‐bleeding autoclave process
Authors: Xin Chaobo , Gu Yizhuo , Li Min , Li Yanxia , Zhang Zuoguang
Published: December 2010

Resin pressure is one of the most important parameters in manufacturing composites during autoclave process. It not only greatly influences resin flow behavior, but also has effects on void formation and elimination. Online monitoring resin pressure can provide an important guidance for the optimization of the processing parameters and the control of the quality of composites. In this study, a resin pressure online measuring system for autoclave process was established based on the principle of pressure transfer in liquid, and the size of the measuring probe of the system was optimized to increase the accuracy of measured resin pressure. The results indicate that the accuracy and the dynamic response of the system can meet the requirements of resin pressure measurement during autoclave process. Furthermore, by means of this proposed resin pressure measuring system and the measurements of compaction properties of the fabric stacks, the resin pressures inside carbon fiber fabric/epoxy resin and glass fiber fabric/epoxy resin prepreg stacks during autoclave process were investigated, especially for the zero‐bleeding process which is prevailing for aircraft composite structures. It is demonstrated that during zero‐bleeding process, the resin pressures, which conform to the spring and piston model, uniformly distribute along through‐thickness and in‐plane directions. In addition, the resin pressure profile is significantly influenced by the fiber volume fraction of the prepregs, indicating that fiber content of prepreg should be optimized for achieving free defects and uniform fiber distribution. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers
Flame retardant effect of polyhedral oligomeric silsesquioxane and triglycidyl isocyanurate on glass fibre‐reinforced epoxy composites
Authors: Wu Kun , Kandola Baljinder K. , Kandare Everson , Hu Yuan
Published: December 2010

Polyhedral oligomeric silsesquioxane (POSS) and triglycidyl isocyanurate (TGIC) were added to an aerospace grade epoxy resin (EP) individually or in combinations at low concentrations. The EP samples containing additives were cast into resin laminates and also used to produce glass fibre‐reinforced composite laminates. The flammability of the two types of laminates was studied by limiting oxygen index, UL‐94 and cone calorimetry. The cone results indicated that the use of POSS (10 wt%) in EP can significantly decrease resin/composite's peak heat release rate, total heat release, and CO production. The mechanical performance in flexural modes of the fibre‐reinforced composite laminates was not adversely affected by the addition of POSS and TGIC in the resin. POSS containing samples had better retention of mechanical properties after exposure to radiant heat in a cone calorimeter compared with other samples. The results of thermogravimetry (TG), TG‐FTIR, and dynamic FTIR indicated that the thermal degradation behavior of the EP is significantly changed by the addition of POSS. POSS can get grafted on the EP's main chain during earlier stages of decomposition and form a stable char layer to protect the underlying material from further decomposition. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers
Multifunctional properties of polyester fabrics modified by corona discharge/air RF plasma and colloidal TiO2nanoparticles
Authors: Mihailović D. , Šaponjić Z. , Molina R. , Radoičić M. , Esquena J. , Jovančić P. , Nedeljković J. , Radetić M.
Published: December 2010

In this study the possibility of tailoring the textile nanocomposite materials based on the polyester fabric and TiO2nanoparticles that can simultaneously provide desirable level of antibacterial activity, UV protection, and self‐cleaning effects with long‐term durability was investigated. To enhance the binding efficiency of colloidal TiO2nanoparticles, the surface of polyester fabrics was activated by low‐pressure RF air plasma, and corona discharge at atmospheric pressure. Obtained functionalized textile materials provided maximum antibacterial efficiency against gram‐negative bacteriumE. coli. High values of UV protection factor (UPF) indicate the maximum UV blocking efficiency (50+) of these fabrics. The results of self‐cleaning test with blueberry juice stains and photodegradation of methylene blue in aqueous solution confirmed excellent photocatalytic activity of TiO2nanoparticles deposited on the fiber surface. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers
Synthesis, characterization, and colloidal properties of polythiophene/borax conducting composite
Authors: Gumus O. Yunus , Unal H. Ibrahim , Erol Ozlem , Sari Bekir
Published: December 2010

In this study, synthesis of polythiophene (PT) and polythiophene/borax pentahydrate (PT/borax) conducting composite were carried out by in‐situ oxidative polymerization. The composite was subjected to various characterization techniques namely: FTIR, particle size, magnetic susceptibility, density, conductivity, dielectric, TGA, XRD, SEM, and zeta (ζ)‐potential measurements. The effects of time, pH, various surfactants, electrolytes and temperature on the ζ‐potential of PT and PT/borax composite were investigated. In a basic medium the ζ‐potential of the composite was observed to decrease up to ζ = −66.5 mV. The most effective surfactant on the ζ‐potential of the composite was sodium dodecyl sulfate, which reduced the value of ζ‐potential to ζ = −39.2 mV. It was concluded that the presence of mono‐valent (NaCl) salt has no impact on ζ‐potential whereas, di‐valent (BaCl2) salt shifted the ζ‐potential value to more positive regions. Elevated temperatures caused almost no change on the ζ‐potential of the composite. Also an electrorheological effect (a tremendous viscosity increase) was determined from the PT/borax colloidal systems under an externally applied electric field, and the results obtained will be discussed in the forthcoming article. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers
Impact of implementing alerts about medication black‐box warnings in electronic health records
Authors: Yu Donghui Tony , Seger Diane L. , Lasser Karen E. , Karson Andrew S. , Fiskio Julie M. , Seger Andrew C. , Bates David W.
Published: December 2010

Background

The Food and Drug Administration issues black‐box warnings (BBWs) regarding medications with serious risks, yet physician adherence to the warnings is low.

Methods

We evaluated the impact of delivering BBW‐based alerts about drug–drug, drug–disease, and drug–laboratory interactions for prescription medications in outpatients in an electronic health record with clinical decision support. We compared the frequency of non‐adherence to all BBWs about drug–drug, drug–disease, and drug–laboratory interactions for 30 drugs/drug classes, and by individual drugs/drug groups with BBWs between the pre‐ and post‐intervention periods. We used multivariate analysis to identify independent risk factors for non‐adherence to BBWs.

Results

There was a slightly higher frequency of non‐adherence to BBWs after the intervention (4.8% vs. 5.1%, p = 0.045). In multivariate analyses, after adjustment for patient and provider characteristics and site of care, medications prescribed during the pre‐intervention period were less likely to violate BBWs compared to those prescribed during the post‐intervention period (OR 0.67, 95% CI, 0.47–0.96). However, black‐box warning violations did decrease after the intervention for BBWs about drug–drug interactions (6.1% vs. 1.8%, p < 0.0001) and drug–pregnancy interactions (5.1% vs. 3.6%, p = 0.01).

Conclusions

Ambulatory care computerized order entry with prescribing alerts about BBWs did not improve clinicians' overall adherence to BBWs, though it did improve adherence for specific clinically important subcategories. Copyright © 2010 John Wiley & Sons, Ltd.
The proportion of patient reports of suspected ADRs to signal detection in the Netherlands: case–control study
Authors: van Hunsel Florence , Talsma Attje , van Puijenbroek Eugène , de Jong‐van den Berg Lolkje , van Grootheest Kees
Published: December 2010

Aim

To determine the contribution of patients' adverse drug reaction (ADR) reports to signals detection, through a study of the signals sent by Lareb to the Dutch Medicines Evaluation Board.

Methods

The percentage of patient's ADR reports contributing to generate signals of adverse drug reactions was determined. A case–control design was used to study if the proportion of patient reports in associations that had been selected as ‘signals’ differed from non‐signals. A logistic regression analysis was used to calculate the Odds Ratio with 95%CI for patient reports in the cases and controls.

Results

The number of patient reports which contributed to a signal has increased from 0 reports in 2003 to 31 reports in 2008 (9% of total). Since 2005 patient reports have triggered particular associations to be selected as a signal. In 2007, 28% of all trigger reports were reported by a patient. The case–control analysis showed that patient reports were equally present in the reports used in signal formation (cases) as in the controls, reports not contributing to a signal. Odds Ratio (OR) was 1.10 (95%CI 0.81−1.49) and OR = 0.96 (95%CI 0.50−1.87) for the ‘trigger reports’.

Conclusions

The proportion of patient reports contributing to generate signals was equal to the proportion of patient reports in the database. Patient's reports of adverse drug reactions can provide a valuable contribution to the detection of signals in addition to healthcare professionals' reports. In the Netherlands, direct patient reports have added to the signals of adverse drug reactions sent to the Medicines Evaluation Board. Copyright © 2010 John Wiley & Sons, Ltd.
Silicon nanowires made via macropore etching for superior Li ion batteries
Authors: Ossei‐Wusu Emmanuel , Cojocaru Ala , Hartz Hauke , Carstensen Jürgen , Föll Helmut
Published: December 2010

The future of electro mobility depends critically on substantially improved Li ion batteries. Si as anode material has a more than tenfold higher capacity as compared to the standard graphite anode, but needs to be nanostructured to avoid fracture. It is shown that macropore etching combined with suitable follow‐up processes allows to produce nanowire arrays with optimized geometries. First tests of these anodes showed very promising results with respect to prime battery parameters like capacity and capacity losses during cycling. In particular, a first test battery showed superior performance for more than 60 cycles in comparison to an otherwise identical battery with a graphite anode. Critical processes like galvanic Cu deposition at the nanowire bottom can be avoided by using an optimized pore etching process that produces complex pore diameter profiles as a function of depth, allowing easy separation of the nanowire layer from the Si substrate and processing the nanowire surface area. In total, the production of Si nanowire anodes using this improved process should allow mass production at competitive costs.

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Si nanowire array for use as a high‐capacity anode in a Li ion battery.
Numerical simulation of copper filling within mesoporous silicon by electrodeposition
Authors: Fukami Kazuhiro , Chourou Mohamed L. , Sakka Tetsuo , Ogata Yukio H.
Published: December 2010

A model of metal electrodeposition within mesoporous silicon is proposed. The model is based on the coupled map lattice model, which includes diffusion of metal ions, electrode shape, equivalent circuit of electrochemical cell, and potential drop in porous silicon wall. Continuous filling from the pore bottom to the opening and plugging at the pore opening were successfully reproduced using the present model. By analyzing the concentration profile of cupric ions in solution, the mechanism of plugging at the pore opening and discontinuous filling by electrodeposition is discussed.
F8BT nanopillars from porous anodic alumina
Authors: Palacios Raquel , Formentín Pilar , Martínez‐Ferrero Eugenia , Ferre‐Borrull Josep , Pallarès Josep , Marsal Lluis F.
Published: December 2010

Poly(9,9‐di‐n‐octylfluorene‐alt‐benzothiadiazole) (F8BT) nanopillars were fabricated using the template wetting method. In order to obtain nanostructures, self‐ordered nanoporous alumina has been employed as template. Environmental scanning electron microscopy (ESEM) images reveal that the resulting F8BT structures present diameters ∼225 nm and heights ∼500 nm. The influence of the template and the solvent in the photophysical properties of the F8BT structures have been studied by UV‐Vis absorption, photoluminescence and Raman spectroscopy. These polymer structures have a wide range of potential applications due to its optical and electrical properties.
Applications of colloidal crystal patterning for synthesis of 1D and 3D nanostructured semiconductors
Authors: Lévy‐Clément Claude , Wang Xiaodong , Benoit‐Moez Charlotte , Elias Jamil , Philippe Laetitia , Michler Johan
Published: December 2010

We report on two different applications of polystyrene (PS) sphere lithography (colloidal crystal patterning). The first example is related to the classical use of PS spheres as a mask, while in the second example, for the first time, the PS spheres are used as a template to grow semiconductors with complex hierarchical structures. Combining PS nanosphere mask and metal‐assisted etching enabled to produce array of well‐ordered silicon nanowires (Si‐NWs) with uniform diameter. Our contribution in this field was to control the formation of extended arrays of 60 nm diameter Si‐NWs on large size Si wafers by downsizing the diameter of the spheres which was nominally 100 nm. The second application is new. By rendering electrically conductive the insulating PS, the spheres were used as a template to grow electrochemically well‐ordered ZnO hollow‐urchins composed of single‐crystal ZnO nanowires (ZnO‐NWs). This new nanostructure exhibited dramatically increased light diffusion properties, making it very promising for use in semiconductor‐sensitized solar cells.
Structure and electronic properties of trivacancy and trivacancy‐oxygen complexes in silicon
Authors: Markevich V. P. , Peaker A. R. , Hamilton B. , Lastovskii S. B. , Murin L. I. , Coutinho J. , Torres V. J. B. , Dobaczewski L. , Svensson B. G.
Published: December 2010

We have recently found that the silicon trivacancy (V3) is a bistable defect that can occur in fourfold coordinated and (110) planar configurations for both the neutral and singly negative charge states [V. P. Markevich et al., Phys. Rev. B 80, 235207 (2009)]. Acceptor levels of V3 in both these configurations have been determined. It has also been shown that at T > 200 °C, the interaction of mobile trivacancies with interstitial oxygen atoms results in the formation of V3O complex with the first and second acceptor levels at Ec −0.46 and −0.34 eV. In the present work we identify donor levels arising from V3 and V3O complexes by means of deep level transient spectroscopy (DLTS) and high‐resolution Laplace DLTS on n+p silicon structures irradiated with 6 MeV electrons, combined with density functional modeling studies. It is found that both defects possess two donor levels in the (110) planar configurations. First donor levels at Ev +0.19 and +0.235 eV, and the second donor levels at Ev +0.105 and +0.12 eV are found for the V3 and V3O complexes, respectively.
Mesenchymal stem cell attachment to peptide density gradients on porous silicon generated by electrografting
Authors: Clements Lauren R. , Wang Peng‐Yuan , Harding Frances , Tsai Wei‐Bor , Thissen Helmut , Voelcker Nicolas H.
Published: December 2010

Chemical gradients of ethyl‐6‐bromohexanoate (EBH) were generated over porous silicon (pSi) substrates via electrochemical attachment. Immobilised ester moieties were hydrolysed and activated to produce a gradient of functional carboxylic acid groups. After subsequent immobilisation of cyclic RGD (cRGD), the surfaces were used to screen the extent of rat mesenchymal stem cell (MSC) attachment. Mapping of surface chemistry was carried out by means of infrared microscopy and X‐ray photoelectron spectroscopy (XPS). MSC culture studies showed that short‐term cell attachment responded to the cRGD density present on the gradient surface.
Mesoporous CeO2 nanopowders with different particle sizes
Authors: Dohčević‐Mitrović Z. , Golubović A. , Radović M. , Fruth V. , Kremenović A. , Meden A. , Babić B. , Šćepanović M. , Popović Z. V.
Published: December 2010

Ultrafine porous cerium dioxide nanopowders were synthesized by relatively new and cost‐effective hydrothermal method varying the main synthesis parameters, temperature of calcination and type of basic solution. Characterization of the as‐produced powders was performed by X‐ray diffraction (XRD), atomic force microscopy (AFM), Raman scattering and Brunauer‐Emmett‐Teller (BET) method. This study reveals that difference in synthesis parameters has strong influence on the particle size, surface area, and pore size distribution enabling the more precise control of material properties very important for catalytic and nanosensor applications.
Ba0.68Sr0.32TiO3/Ba0.68Sr0.32TiO3 + Mn composite with low loss and high pyroelectric coefficient
Authors: Zhang Guangzu , Jiang Shenglin , He Jungang , Wang Jing , Zhang Qingfeng , Zhang Yangyang , Yu Yan
Published: December 2010

Pure barium strontium titanate (BST) and 10 mol% Mn(NO)3 doped BST were combined in a three‐dimensional structure, and the dielectric and pyroelectric properties of the ceramics were investigated. Compared with conventional doped ceramics, samples with the three‐dimensional structure exhibited excellent properties. When Mn was added in this special structure, the dielectric loss was depressed dramatically. However, the dielectric constant peak depression effect caused by the dopants was weakened simultaneously. This phenomenon was nontraditional but conducive to the improvement of pyroelectric properties of BST as dielectric bolometer. The dielectric loss, pyroelectric coefficient, and flgure‐of‐merit of three‐dimensional structural specimens could be 0.5%, 9500 µC/m2 K, and 18.0 × 10−5 Pa−0.5, respectively. All these properties were better than samples prepared by conventional doping method. The improvement of pyroelectric property is beneficial for the development of infrared detectors.
Growth and structural characterization of ferromagnetic Cr‐doped GaN nanowires
Authors: Chun JungHwan , Kim DongEon
Published: December 2010

Cr‐doped GaN nanowires have been proposed to be ferromagnetic, resulting from a charge overlap between the N 2p and Cr 3d states and to be more robust than Mn‐doped GaN nanowires. We demonstrated the successful fabrication of single‐crystalline GaN nanowires doped with Cr, which show ferromagnetism at room temperature. The structural study shows that these nanowires have diameters of several tens of nm to a few 100 nm and are single crystalline with a Cr doping concentration of about 2.06 at%.
Fragmentation patterns of novel dithiocarbamate derivatives with pharmaceutical activity under electrospray ionization tandem mass spectrometry conditions
Authors: Wang Xin , Sha Yaowu , Ge Zemei , Wang Wei , Li Runtao
Published: December 2010

The fragmentation patterns of a novel series of dithiocarbamate derivatives with pharmaceutical activity were investigated by positive ion electrospray ionization mass spectrometry in conjunction with tandem mass spectrometry (ESI‐MSn). In the gas phase, the dithiocarbamate protonated molecules containing the piperazinium moiety undergo losses of bromide to form the piperazinium cation by ionization, followed by subsequent losses of methyl bromide, ring opening and rearrangement of piperazinium. Furthermore, the dithiocarbamate derivatives and their intermediates both undergo cleavage of the C–S bond to produce two common fragment ions. The different fragmentation observed for these compounds facilitated their identification and could be valuable in the further study of their metabolic pathways as prodrugs. Copyright © 2010 John Wiley & Sons, Ltd.
A strategy for liquid chromatography/tandem mass spectrometry based quantitation of pegylated protein drugs in plasma using plasma protein precipitation with water‐miscible organic solvents and subsequent trypsin digestion to generate surrogate peptides for detection
Authors: Wu Steven T. , Ouyang Zheng , Olah Timothy V. , Jemal Mohammed
Published: December 2010

Recently, we have developed liquid chromatography/tandem mass spectrometry (LC/MS/MS)‐based methods for the quantitation of pegylated therapeutic proteins in plasma. The methods are based on the LC/MS/MS detection of a surrogate peptide generated from trypsin digestion of the therapeutic protein. Various parameters related to the bioanalytical methods were evaluated and optimized, including the preparation of calibration standards and quality control samples, sample extraction, internal standard selection and its stage of addition, trypsin digestion, and non‐specific binding. In this paper, we report the development of a method for a specific pegylated therapeutic protein and detail the various optimization steps undertaken. Simple extraction of the pegylated therapeutic protein from plasma was achieved via the precipitation of the endogenous proteins in plasma using acidic isopropanol and the resulting supernatant extract was subjected to trypsin digestion. A unique tryptic peptide arising from the pegylated therapeutic protein was used for LC/MS/MS‐based detection and quantitation. A protein and a peptide were used as internal standards, with the former added before the sample extraction and the latter after the sample extraction. The method developed is simple, sensitive, specific and rugged, and has been implemented in a high throughput 96‐well format to analyze plasma samples from in vivo studies. A required lower limit of quantitation (LLOQ) of 10 ng/mL, expressed in terms of the concentration of the protein drug, was easily achieved. Copyright © 2010 John Wiley & Sons, Ltd.
OPTIMIZING ENVIRONMENTAL FLOWS BELOW DAMS
Authors: Yin X. A. , Yang Z. F. , Petts G. E.
Published: December 2010

The protection of riverine ecosystems downstream from dams requires reservoir operations to satisfy environmental flow (e‐flow) requirements. In practice, this often involves re‐regulation of downstream river flows within the constraints of water resource demands for human supplies and irrigation. In this paper, we develop a method to assess how reservoir storage may be used more effectively to meet both water supply and downstream ecosystem needs. The latter are met by providing seasonally variable baseflows, including dry season flow recession at natural rates, and high‐flow pulses and bankfull flows synchronized with natural events. A series of reservoir operating rules are derived based on both reservoir storage and reservoir inflows to trigger reservoir releases. For a given water supply reliability, the method seeks to minimize the degree of hydrological alteration below a dam. We present a case study of the Tanghe Reservoir in China's Tang river basin to show that the proposed method could help reservoir managers and planners evaluate e‐flow scenarios to reduce the negative impacts of dams and reservoirs on riverine ecosystems. Copyright © 2010 John Wiley & Sons, Ltd.
AFM image processing for estimating the number and volume of nanoparticles on a rough surface
Authors: Liu Qinghua , Wang Huiliang , Liu Jun , Huang Haiyang
Published: December 2010

This article presents the method of computer automatic recognition and measurement of the number and volume of nanoparticles formed on a rough surface by smoothing, enhancement and segmentation of image processing. The grafted grains (nanoparticles) on polyethylene surface are taken as the example. This method uses shock filter enhancement and globally convex segmentation to separate the nanoparticles from the polymer substrate surface. Then the nanoparticles are extracted from the rough surface, and the number and volume of nanoparticles on the rough surface are determined. By applying this method to analyze the surfaces irradiated for different time, the number and volume of grafted grains are obtained and they are consistent with the results obtained manually. Copyright © 2010 John Wiley & Sons, Ltd.
Ultrasensitive Detection of Low‐Abundance Surface‐Marker Protein Using Isothermal Rolling Circle Amplification in a Microfluidic Nanoliter Platform
Authors: Konry Tania , Smolina Irina , Yarmush Joel M. , Irimia Daniel , Yarmush Martin L.
Published: December 2010

With advances in immunology and cancer biology, there is an unmet need for increasingly sensitive systems to monitor the expression of specific cell markers for the development of new diagnostic and therapeutic tools. To address this challenge, a highly sensitive labeling method that translates antigen–antibody recognition processes into DNA detection events that can be greatly amplified via isothermal rolling circle amplification (RCA) is applied. By merging the single‐molecule detection power of RCA reactions with microfluidic technology, it is demonstrated that the identification of specific protein markers can be achieved on tumor‐cell surfaces in miniaturized nanoliter reaction droplets. Furthermore, this combined approach of signal amplification in a microfluidic format could extend the utility of existing methods by reducing sample and reagent consumption and enhancing the sensitivities and specificities for various applications, including early diagnosis of cancer.
Receptor‐Mediated Interactions between Colloidal Gold Nanoparticles and Human Umbilical Vein Endothelial Cells
Authors: Bartczak Dorota , Sanchez‐Elsner Tilman , Louafi Fethi , Millar Timothy M. , Kanaras Antonios G.
Published: December 2010

A new strategy to manipulate cell operations is demonstrated, based on membrane‐receptor‐specific interactions between colloidal peptide‐capped gold nanoparticles and human umbilical vein endothelial cells. It is shown that colloidal gold nanoparticles of similar charge and size but capped with different peptide sequences can deliberately trigger specific cell functions related to the important biological process of blood vessel growth known as angiogenesis. Specific binding of the peptide‐capped particles to two endothelial‐expressed receptors (VEGFR‐1, NRP‐1), which control angiogenesis, is achieved. The cellular fate of the functional nanoparticles is imaged and the influence of the different peptide‐coated nanoparticles on the gene expression profile of hypoxia‐related and angiogenic genes is monitored. The findings open up new avenues towards the deliberate biological control of cellular functions using strategically designed nanoparticles.
Nanopore Biosensors: Monitoring of an ATP‐Binding Aptamer and its Conformational Changes Using an α‐Hemolysin Nanopore (Small 1/2011)
Authors: Ying Yi‐Lun , Wang Hai‐Yan , Sutherland Todd C. , Long Yi‐Tao
Published: December 2010

An aptamer is a specific oligonucleotide sequence that spontaneously forms a secondary structure capable of selectively binding an analyte. An aptamer’s conformation is the key to specific binding of a target molecule, even in the case of very closely related targets. Nanopores are a sensitive tool for the single‐molecule analysis of DNA, peptides, and proteins transporting through the pore. Herein, a single α‐hemolysin natural nanopore is utilized to sense the conformational changes of an adenosine 5’‐triphosphate (ATP)‐binding aptamer (ABA). The known DNA sequence of the ABA is used as a model to develop real‐time monitoring of molecular conformational changes that occur by binding targets. The native, folded ABA structure has a nanopore unfolding time of 4.17 ms, compared with 0.29 ms for the ABA:ATP complex. A complementary 14‐mer strand, which binds the ABA sequence in the key nucleic acids responsible for folding, forms linear duplex DNA, resulting in a nanopore transit time of 0.50 ms and a higher capture probability than that of the folded ABA oligomer. Competition assays between the ABA:ATP and ABA:reporter complexes are carried out, and the results suggest that the ABA:ATP complex is formed preferentially. The nanopore allows for the detection of an ABA in its folded, ATP‐bound, and linear conformations.
Differential Calculation Model for Liquidus Temperature of Steel
Authors: Wang Xin , Wang Xianyong , Wang Bao , Wang Bin , Liu Qing
Published: December 2010

The liquidus temperature of steel is greatly affected by its chemical composition; therefore, the value of the liquidus temperature can vary among different types of steel. In this study, on the basis of the concept of differentiation, the Fe‐i binary phase diagram is analyzed using Photoshop image processing software. The effects of eleven common alloying elements (C, Si, Mn, P, S, Ca, Ni, Cu, Cr, Nb, and Mo, whose content is between 0%∼4%) on the melting point of pure iron are analyzed. This analysis proves the following assumption to be incorrect: the relationship between the change in liquidus temperature and the content of element i is a linear relationship; this assumption is the basis of traditional liquidus calculation models. A new model for calculating the liquidus temperature of steel is established in this study. As compared to data from other literature, the model proposed in this paper has good generality and the calculation error of the liquidus temperature of steel is between −3 and 4 °C, which is acceptable. A statistical analysis of the experimental data for different steel grades (obtained from Laiwu Special Steel) using the developed model showed that 87.2% of the absolute deviation values of the temperature are within 4 °C. This result shows the model to be both reasonable and credible.
Effects of Mold Powder Chemistry on Shell Growth, Momentum and Heat Transfer in a Billet Mold
Authors: Nájera‐Bastida A. , Morales R.D. , García‐Demedices L. , Zárate‐Gutiérrez R. , Rodríguez‐Ávila J.
Published: December 2010

Effects of mold powder chemistry on shell growth and thinning have been studied using Computer Fluid Dynamic techniques under conditions of constant casting speed and steel superheat for a peritectic steel in a billet caster. Two mold powders were considered; a basic powder suitable for peritectic steels and an acid powder not recommendable for this steel in order to emphasize the importance of chemistry on shell stability. Numerical results indicate a strong interaction between powder composition and steel flow‐heat transfer phenomena. The acid powder creates recirculating flows at both sides of the entry jet that transport sensible heat to the shell inducing its remelting and thinning leading, eventually, to a strand breakout. Meanwhile, the basic powder induces a single recirculating flow in the internal radius side of the mold without severe shell thinning. A colder meniscus is predicted using the acid powder which is in agreement with the casting practice experience. Powder infiltration of the basic powder in between the mold hot wall and the strand provides a powder shell with a macroscopically smooth surface while the acid powder yields irregular infiltration. Buoyancy forces along the mold working height and mold curvature play a fundamental role on the generation of the recirculating flows. Interaction between powder chemistry and fluid flow‐heat transfer are two‐way coupled phenomena that must be considered for powder design purposes.
Synthesis and Characterization of Fe2MoO4 as a Precursor Material for Mo Alloying in Steel
Authors: Chychko A. , Teng L. , Nzotta M. , Seetharaman S.
Published: December 2010

Iron molybdate (Fe2MoO4) has been studied as a new potential precursor for Mo additions in high alloy steel processing. Fe2MoO4 was synthesized by high temperature reactions between MoO3, FeOx and carbon by holding the mixture first for 23 hours at 873 K and then for 16 hours at 1373 K. The Fe2MoO4 syntheses were carried out with pure reagents as well as commercial grade materials supplied by steel industry. A thermodynamic analysis of the stabilities of the various phases in the Fe‐Mo‐O‐C quaternary was carried out. The synthesis processes, leading to the Fe2MoO4 formation from the precursors and further reduction by carbon were studied with the aid of thermogravimetric analysis (TGA), high‐temperature X‐ray diffraction (HT‐XRD) and evolved gas analysis by gas chromatography (GC). The maximum temperature in the case of all the experiments was 1373 K. It was found that the reactions between the precursor components start already above 873 K. The precursor mixture from commercial grade materials offers an economically advantageous process route with high Mo yield in steel.
Cold Simulation of Particle Movement in a Conducting Liquid under Crossed Electric and Magnetic Fields. Magnetite Particles Separation from Molten Slags
Authors: Semykina A. , Gorobets O. , Shatokha V. , Seetharaman S.
Published: December 2010

The experimental technique of mobilising non‐conducting, nonmagnetic particles in conducting liquid in crossed electric and magnetic fields was investigated in order to find the way of the particle separation from the liquid steelmaking slags. The effect of the current density, magnetic field, size and shape of the particle on the particle velocity under action of the electromagnetic buoyancy force (EBF) in the electrolyte was analysed.

Potential way of the application of obtained results to magnetite particle separation from liquid EAF slags are discussed.