bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Irradiation Temperature on Grafting of Styrene into Poly(tetrafluoroethylene‐co‐hexafluoropropylene) Films
Authors: Lappan Uwe , Geißler Uwe , Gohs Uwe , Uhlmann Steffi
Published: July 2009

This study concerns with the investigation of the effect of irradiation conditions on grafting of styrene into FEP films by the pre‐irradiation method. EPR spectroscopy was used to characterize the base polymer material regarding the trapped radical species and their concentration. Radiation‐induced changes in the chemical structure were studied by IR spectroscopy. Tensile strength and elongation at break as well as yield of grafting were found to be strongly influenced by irradiation temperature. Main‐chain scissions were identified to be the reason for the deterioration of the mechanical properties after radiation treatment at temperatures below glass transition temperature.

magnified image
Effect of Reprocessing Cycles on the Morphology and Properties of Poly(propylene)/Wood Flour Composites Compatibilized with EBAGMA Terpolymer
Authors: Kaci Mustapha , Hamma Amel , Pillin Isabelle , Grohens Yves
Published: July 2009

The present study is aimed to investigate the effect of multiple extrusions of iPP/WF composites with and without EBAGMA used as compatibilizer. The degradation induced by the recycling processes was evaluated through changes in molecular structure, morphology, rheology, thermal and mechanical properties. The results showed that after six cycles, the presence of WF imparts stability to the composite materials. This effect was enhanced for the compatibilized samples. Further, SEM revealed better dispersion of the WF in the matrix. In contrast, it was confirmed that after the first recycling, both the molecular weight and the properties of PP drastically decreased due to chain scission resulting from degradation.

magnified image
Defined Poly[styrene‐block‐(ferrocenylmethyl methacrylate)] Diblock Copolymers via Living Anionic Polymerization
Authors: Gallei Markus , Schmidt Bernhard V. K. J. , Klein Roland , Rehahn Matthias
Published: July 2009

Ferrocenylmethyl methacrylate (FMMA) is one of the very few metallocene‐based monomers that are promising candidates for truly living anionic polymerization. Nevertheless, FMMA homopolymers with a narrow polydispersity, or block copolymerization studies that result in satisfying blocking efficiencies, are unknown so far. Here we describe a procedure that leads to highly regular FMMA‐based polymers for the first time, characterized by polydispersity indices (PDI) of less that 1.05 and very high blocking efficiencies (>95%) in sequential copolymerization with styrene. Some of the obtained poly[styrene‐block‐(ferrocenylmethyl methacrylate)]s show unusual microphase morphologies, presumably the consequence of high Tgs causing ‘frustrated’ non‐equilibrium states.

magnified image
Relationship of Photophysical Properties and the Device Performance of Novel Hybrid Small‐Molecular/Polymeric Solar Cells
Authors: Inal Sahika , Castellani Mauro , Sellinger Alan , Neher Dieter
Published: July 2009

We investigate solar cells comprised of a vinazene derivative (HV‐BT) as the electron acceptor and the well‐known polymer poly(3‐hexylthiophene) as the electron donor. In the as‐prepared blend, most of the excited state species, including the excimers on HV‐BT, are quenched at the heterojunction. Although the photophysical properties of the blends change upon annealing, the blend solar cells largely remain uninfluenced by such treatments. A significant improvement is, however, observed when inducing phase separation at a longer length scale, for example, in solution‐processed bilayer devices. Hereby, both the fill factor (FF) and the open circuit voltage are considerably increased, pointing to the importance of the heterojunction topology and the layer composition at the charge extracting contacts. An optimized device exhibits a power conversion efficiency of close to 1%.

magnified image
Damping Behavior of the Aggregation–Disaggregation Self‐Oscillation of a Polymer Chain
Authors: Hara Yusuke , Yoshida Ryo
Published: July 2009

The effect of the initial concentration of the substrates of the Belousov–Zhabotinsky (BZ) reaction, and the temperature, on the autonomous aggregation–disaggreagtion self‐oscillation of a polymer chain is investigated. The polymer chain consists ofN‐isopropylacrylamide (NIPAAm), a Ru catalyst of the BZ reaction, and acrylamide‐2‐methylpropanesulfonic acid (AMPS) as a pH and solubility control site. It is demonstrated that the initial concentration of the BZ substrates and the temperature exert an influence on the waveform and the period of the self‐oscillation. Moreover, the aggregation–disaggregation self‐oscillation of the polymer chain undergoes damping, that is, the amplitude of the transmittance self‐oscillation decreases with time. This phenomenon is attributed to an increase in the size of the polymer aggregates during the self‐oscillating behavior. Therefore, the damping behavior is significantly affected by the initial concentration of the BZ substrates in accordance with the Field–Körös–Noyes (FKN) mechanism. In addition, it is shown that the self‐oscillating region is determined by the initial concentrations of the BZ substrates and the temperature. This study clarifies that the self‐oscillation of the AMPS‐containing polymer chain can be controlled by the selection of the initial concentration of the BZ substrates and the temperature under acid‐free conditions.

magnified image
A review of current applications of mass spectrometry for neuroproteomics in epilepsy
Authors: Liu Xinyu , Wen Fuqiang , Yang Jinliang , Chen Lijuan , Wei Yu‐Quan
Published: July 2009

The brain is unquestionably the most fascinating organ, and the hippocampus is crucial in memory storage and retrieval and plays an important role in stress response. In temporal lobe epilepsy (TLE), the seizure origin typically involves the hippocampal formation. Despite tremendous progress, current knowledge falls short of being able to explain its function. An emerging approach toward an improved understanding of the complex molecular mechanisms that underlie functions of the brain and hippocampus is neuroproteomics. Mass spectrometry has been widely used to analyze biological samples, and has evolved into an indispensable tool for proteomics research. In this review, we present a general overview of the application of mass spectrometry in proteomics, summarize neuroproteomics and systems biology‐based discovery of protein biomarkers for epilepsy, discuss the methodology needed to explore the epileptic hippocampus proteome, and also focus on applications of ingenuity pathway analysis (IPA) in disease research. This neuroproteomics survey presents a framework for large‐scale protein research in epilepsy that can be applied for immediate epileptic biomarker discovery and the far‐reaching systems biology understanding of the protein regulatory networks. Ultimately, knowledge attained through neuroproteomics could lead to clinical diagnostics and therapeutics to lessen the burden of epilepsy on society. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 29:197–246, 2010
Accurate and precise determination of isotopic ratios by MC‐ICP‐MS: A review
Authors: Yang Lu
Published: July 2009

For many decades the accurate and precise determination of isotope ratios has remained a very strong interest to many researchers due to its important applications in earth, environmental, biological, archeological, and medical sciences. Traditionally, thermal ionization mass spectrometry (TIMS) has been the technique of choice for achieving the highest accuracy and precision. However, recent developments in multi‐collector inductively coupled plasma mass spectrometry (MC‐ICP‐MS) have brought a new dimension to this field. In addition to its simple and robust sample introduction, high sample throughput, and high mass resolution, the flat‐topped peaks generated by this technique provide for accurate and precise determination of isotope ratios with precision reaching 0.001%, comparable to that achieved with TIMS. These features, in combination with the ability of the ICP source to ionize nearly all elements in the periodic table, have resulted in an increased use of MC‐ICP‐MS for such measurements in various sample matrices. To determine accurate and precise isotope ratios with MC‐ICP‐MS, utmost care must be exercised during sample preparation, optimization of the instrument, and mass bias corrections. Unfortunately, there are inconsistencies and errors evident in many MC‐ICP‐MS publications, including errors in mass bias correction models. This review examines “state‐of‐the‐art” methodologies presented in the literature for achievement of precise and accurate determinations of isotope ratios by MC‐ICP‐MS. Some general rules for such accurate and precise measurements are suggested, and calculations of combined uncertainty of the data using a few common mass bias correction models are outlined. © 2009 Crown in the right of Canada. Published by Wiley Periodicals, Inc., Mass Spec Rev 28:990–1011, 2009
Rissfortschritts‐ und Ermüdungsverhalten der Aluminiumlegierung EN AW‐6060 nach ECAP und nachgelagerter Wärmebehandlung
Authors: Hockauf K. , Meyer L.W. , Halle T. , Hockauf M.
Published: July 2009

An der warmaushärtenden Aluminiumlegierung EN AW‐6060 wurden Untersuchungen zum Rissfortschritt und zur Ermüdung nach hochgradig plastischer Verformung durch ECAP (Equal‐Channel Angular Pressing) durchgeführt. Es wurden Zustände in unterschiedlichen Stadien der Mikrostrukturfeinung und Verformungsverfestigung untersucht: ein bimodaler Zustand nach zwei sowie ein homogen ultrafeinkörniger Zustand nach acht ECAP‐Umformschritten. Zudem wurden zwei optimierte Zustände mit verbesserter Duktilität, eingestellt durch eine Kombination aus ECAP mit einer nachfolgenden kurzen Auslagerungsbehandlung, in die Untersuchungen einbezogen. Rissfortschrittsversuche im Schwellwertbereich und dem stabilen Rissfortschrittsbereich bei Lastverhältnissen von R = 0,1 bis 0,7 ergaben für die optimierten Zustände eine Verbesserung der Schwellwerte im Vergleich zu den ecapierten Zuständen, was auf erhöhte Duktilität durch die Kombination von ECAP und einer Auslagerungsbehandlung zurückgeführt wurde. Anhand von rasterelektronenmikroskopischen Analysen der Rissfortschrittsflächen sowie den aus Zugversuchen ermittelten Festigkeits‐ und Zähigkeitskennwerten konnte das Rissfortschrittsverhalten mit der Mikrostruktur und den mechanischen Eigenschaften in Verbindung gebracht werden. In Ermüdungsversuchen im Zeitfestigkeitsbereich (HCF „high cycle fatigue”︁) wurden ein ecapierter sowie ein optimierter Zustand untersucht. Für beide Zustände wurde eine deutliche Erhöhung der Ermüdungsfestigkeit im Vergleich zum Ausgangszustand festgestellt.
Umformende Herstellung von Al/Mg‐Werkstoffverbunden
Authors: Neugebauer R. , Glaß R. , Popp M. , Nickel D.
Published: July 2009

Eine allgemeingültige Theorie über die Bindevorgänge metallischer Werkstoffe ist nicht bekannt. Für jede neue Werkstoffkombination und jedes neue Umformverfahren sind die Bindevorgänge wiederholt zu untersuchen, um die für eine ausreichende Haftfestigkeit der Verbundpartner erforderlichen Parameter zu ermitteln. Im Folgenden wird eine Methode beschrieben, welche durch einen Umformprozess einen Werkstoffverbund erzeugt und zukünftig die Möglichkeit bietet, relevante Parameter gezielt auf ihre verbundfördernde Wirkung hin zu untersuchen.
Auslegung beschichteter Werkzeuge zur Umformung hochfester Aluminiumwerkstoffe
Authors: Neugebauer R. , Schmidt G. , Stark S. , Wielage B. , Wank A. , Rupprecht C. , Lampke T.
Published: July 2009

Für hochbeanspruchte und sicherheitsrelevante Bauteile werden zunehmend hochfeste Aluminiumwerkstoffe eingesetzt, bei deren Umformung die Werkzeuge stark beansprucht werden. Besonders die stark abrasiven Eigenschaften hochfester Aluminiumwerkstoffe und deren Neigung zum Anhaften auf Werkzeugoberflächen erfordern den Einsatz von Schmier‐ und Trennmitteln. Im Sinne des Umweltschutzes und verbesserter Energieeffizienz wird der Verzicht auf derartige Hilfsstoffe angestrebt. Die tribologischen Verhältnisse zwischen Werkzeug und Werkstück sollen dazu durch geeignete Oberflächenbehandlungen oder Beschichtungen entsprechend beeinflusst werden. Bei der Auslegung beschichteter Umformwerkzeuge müssen die dadurch veränderten Oberflächeneigenschaften und die daraus resultierenden Beanspruchungen berücksichtigt werden. Ausgehend von der Auswahl und Optimierung geeigneter Beschichtungen werden im Teilprojekt B1 des SFB 692 deshalb unter Einsatz numerischer Simulationen mittels FEM Gestaltungsrichtlinien für die Auslegung und Anwendung beschichteter Umformwerkzeuge entwickelt.
Einfluss der Mikrostruktur auf das Verschleiß‐ verhalten der hartanodisierten Aluminium‐legierungen EN AW‐6082 und EN AW‐7075
Authors: Nickel D. , Lampke Th. , Alisch G. , Steinhäuser S.
Published: July 2009

Die Eignung des Hartanodisierens der hochfesten Aluminiumlegierung EN AW‐7075 (Werkstoffzustand T651) zur Herstellung von Verschleißschutzschichten, die auch für Schrauben aus diesem Werkstoff geeignet sind, wurde untersucht. Als Referenzmaterial diente die mittelfeste, i. Allgm. als gut anodisierbar eingestufte Legierung EN AW‐6082 (Werkstoffzustand T6).

Nach möglichen Relaxationserscheinungen einer Schraubverbindung kann die Oberfläche der tragenden Gewindegänge einer Schraube oszillierenden Relativbewegungen ausgesetzt sein. Diese dann sehr schädigend wirkende tribologische Beanspruchung wurde auf einem Schwingverschleißprüfstand mit o. g. Werkstoffen simuliert. Die Ergebnisse zeigten, dass die unbehandelten Oxidschichten auf der Legierung EN AW‐6082 gegenüber der o. g. tribologischen Belastung keinen ausreichenden Schutz bieten. Da Heißwasserverdichten der Schichten zwar die Schichthärte erhöht, aber die Gefahr eines technologisch bedingten Festigkeitsverlustes des Substratwerkstoffs birgt, wurde nach anderen tribologischen Schutzmöglichkeiten gesucht. Die Auswertung der tribologischen Untersuchungen (Charakterisierung des Werkstoffaufbaues und der daraus resultierenden Eigenschaften, Messung der Verschleißbeträge, Beurteilung der Verschleißerscheinungsformen) hat ergeben, dass die mit einer Wachsemulsion versiegelten Oxidschichten beider Substratwerkstoffe einer Schwingverschleißbeanspruchung am besten widerstehen. Auch die ermittelten Schichtrauheiten, Reibwerte und Härtewerte bestätigen das positive Verhalten aller untersuchten anodisch oxidierten Varianten der EN AW‐7075‐Legierung unter der gewählten tribologischen Beanspruchung.
ECAP‐Umformung mittel‐ und hochfester ausscheidungshärtbarer Aluminiumknetlegierungen
Authors: Hockauf M. , Schönherr R. , Wagner S. , Meyer L. W. , Podlesak H. , Mücklich S. , Wielage B. , Krüger L. , Hahn F. , Weber D.
Published: July 2009

Die Studie befasst sich mit der Eigenschaftsoptimierung verschiedener mittel‐ und hochfester Aluminiumknetlegierungen. Im Fokus steht die Optimierung von Prozessabfolgen mit denen im Vergleich zu den kommerziell verfügbaren Referenzzuständen deutlich bessere mechanische Eigenschaften eingestellt werden können. Für das Al‐Mg‐Si‐ und das Al‐Cu‐Mg‐Si‐System wird gezeigt, dass die ECAP‐Umformung sehr hohe Festigkeiten ermöglicht. Je größer der Legierungsgehalt bzw. Aushärtegrad ist, desto höhere Festigkeiten und geringere Korngrößen können durch ECAP erreicht werden. Ebenso extrem verfestigend wirkt sich das Vorhandensein einer keramischen Verstärkungskomponente in Partikelform aus. Durch die Kombination der ECAP‐Umformung mit einer vor‐ bzw. nachgelagerten Wärmebehandlung kann einerseits die Umformbarkeit verbessert werden, was die Werkzeugbelastungen reduziert, und andererseits die Duktilität des Werkstoffes angehoben werden. Dieser positive Effekt wird insbesondere bei niedrigen Legierungsgehalten bzw. hohen Auslagerungstemperaturen beobachtet und kann mit der Wechselwirkung von verformungsinduzierten Gitterdefekten und Ausscheidungen erklärt werden. Durch eine geeignete Wahl der Prozessparameter (Wärmebehandlungszustand, ECAP‐Umformgrad, ‐temperatur, ‐gegendruck) lässt sich so eine optimale Kombination von Festigkeit und Duktilität mit herausragenden Eigenschaftswerten sehr wirtschaftlich einstellen. Aufgrund der allgemein schlechten Umformbarkeit der höchstfesten Legierung EN AW‐7075 (Al‐Zn‐Mg‐Cu ‐ System) konnte mit Hilfe der ECAP‐Umformung bisher keine signifikante Eigenschaftsverbesserung erzielt werden.
Pulvermetallurgische Erzeugung von SiC‐ und Al2O3‐verstärkten Al‐Cu‐Legierungen
Authors: Podlesak H. , Siebeck S. , Mücklich S. , Hockauf M. , Meyer L.W. , Wielage B. , Weber D.
Published: July 2009

Auf der Basis von Schliffuntersuchungen werden die Stadien der Verbundpulver‐Ausbildung bei dem Hochenergiekugelmahlen von Al‐Legierungspulver EN AW‐2017 mit 5 und 15 Vol.‐% SiC‐ bzw. Al2O3‐Pulver der Kornfraktion <2 μm dargestellt. Die erforderliche Mahldauer liegt mit ca. vier Stunden in einem technologisch sinnvollen Rahmen. Der Eintrag von eisenhaltigen Teilchen in das Verbundpulver wird auf den Erosionseffekt an der Stahloberfläche der Rotorflügel, Stahlkugeln und Wand in der Mahlkammer zurückgeführt. Für beide Hartstoffmaterialien wird eine akzeptable Partikelverteilung erreicht, jedoch wird ein weiteres Verbesserungspotenzial gesehen. Eine detaillierte Beschreibung der nach heißisostatischem Pressen und Strangpressen eingestellten Mikrostruktur des Kompaktmaterials erfolgt anhand von raster‐ und transmissionselektronenmikroskopischen Untersuchungen. Für beide Verstärkungsarten ergeben sich analoge Gefüge mit geringer Mikroporosität. Die Grenzfläche Verstärkungspartikel/Matrix weist weder Mikrospalte noch Ansammlungen von spröden Phasen auf. Im Fall der SiC‐Verstärkung ist eine Grenzflächenwechselwirkung in geringem Umfang nachweisbar, was auf eine gute Teilcheneinbindung und ein nicht schädliches Reaktionsausmaß schließen lässt. Das Hochenergie‐Kugelmahlen an Luftatmosphäre bewirkt einen deutlichen Sauerstoffeintrag und die Ausbildung der Spinell‐Phase MgAl2O4 während der nachfolgenden pulvermetallurgischen Verarbeitung. Aufgrund der Größe, Häufigkeit und Verteilung der Spinell‐Teilchen in der Metallmatrix wird ein zusätzlicher Verstärkungseffekt erwartet.
Involvement of GATA transcription factors in the regulation of endogenous bovine interferon‐Tau gene transcription
Authors: Bai Hanako , Sakurai Toshihiro , Kim Min‐Su , Muroi Yoshikage , Ideta Atsushi , Aoyagi Yoshito , Nakajima Hiromi , Takahashi Masashi , Nagaoka Kentaro , Imakawa Kazuhiko
Published: July 2009

Expression of interferon‐tau (IFNT), necessary for pregnancy establishment in ruminant ungulates, is regulated in a temporal and spatial manner. However, molecular mechanisms by which IFNT gene transcription is regulated in this manner have not been firmly established. In this study, DNA microarray/RT‐PCR analysis between bovine trophoblast CT‐1 and Mardin–Darby bovine kidney (MDBK) cells was initially performed, finding that transcription factors GATA2, GATA3, and GATA6 mRNAs were specific to CT‐1 cells. These mRNAs were also found in Days 17, 20, and 22 (Day 0 = day of estrus) bovine conceptuses. In examining other bovine cell lines, ovary cumulus granulosa (oCG) and ear fibroblast (EF) cells, GATA2 and GATA3, but not GATA6, were found specific to the bovine trophoblast cells. In transient transfection analyses using the upstream region (−631 to +59 bp) of bovine IFNT gene (bIFNT, IFN‐tau‐c1), over‐expression of GATA2/GATA3 did not affect the transcription of bIFNT‐reporter construct in human choriocarcinoma JEG3 cells. Transfection of GATA2, GATA3, ETS2, and/or CDX2, however, was effective in the up‐regulation of the bIFNT construct transfected into bovine oCG and EF cells. One Point mutation studies revealed that among six potential GATA binding sites located on the upstream region of the bIFNT gene, the one next to ETS2 site exhibited reduced luciferase activity. In CT‐1 cells, endogenous bIFNT gene transcription was up‐regulated by over‐expression of GATA2 or GATA3, but down‐regulated by siRNA specific to GATA2 mRNA. These data suggest that GATA2/3 is involved in trophoblast‐specific regulation of bIFNT gene transcription. Mol. Reprod. Dev. 76: 1143–1152, 2009. © 2009 Wiley‐Liss, Inc.
BOLD‐specific cerebral blood volume and blood flow changes during neuronal activation in humans
Authors: Chen J. Jean , Pike G. Bruce
Published: July 2009

To understand and predict the blood‐oxygenation level‐dependent (BOLD) fMRI signal, an accurate knowledge of the relationship between cerebral blood flow (ΔCBF) and volume (ΔCBV) changes is critical. Currently, this relationship is widely assumed to be characterized by Grubb's power‐law, derived from primate data, where the power coefficient (α) was found to be 0.38. The validity of this general formulation has been examined previously, and an α of 0.38 has been frequently cited when calculating the cerebral oxygen metabolism change (ΔCMRo2) using calibrated BOLD. However, the direct use of this relationship has been the subject of some debate, since it is well established that the BOLD signal is primarily modulated by changes in ‘venous’ CBV (ΔCBVv, comprising deoxygenated blood in the capillary, venular, and to a lesser extent, in the arteriolar compartments) instead of total CBV, and yet ΔCBVv measurements in humans have been extremely scarce. In this work, we demonstrate reproducible ΔCBVv measurements at 3 T using venous refocusing for the volume estimation (VERVE) technique, and report on steady‐state ΔCBVv and ΔCBF measurements in human subjects undergoing graded visual and sensorimotor stimulation. We found that: (1) a BOLD‐specific flow‐volume power‐law relationship is described by α = 0.23 ± 0.05, significantly lower than Grubb's constant of 0.38 for total CBV; (2) this power‐law constant was not found to vary significantly between the visual and sensorimotor areas; and (3) the use of Grubb's value of 0.38 in gradient‐echo BOLD modeling results in an underestimation of ΔCMRo2. Copyright © 2009 John Wiley & Sons, Ltd.
Sources of local government extractive capacity: The role of trust and pre‐colonial legacy in the case of Uganda
Authors: Kjær Anne Mette
Published: July 2009

Local government extractive capacity, as measured by the amount of graduated personal tax (GPT) collected relative to district wealth and population and, more qualitatively, as reflected in the nature of enforcement, varies considerably in Uganda. This article explores the reasons for this variation, first by investigating aggregate data at the cross‐district level, using data on taxation as well as survey data from the Afrobarometer, second, by a focussed comparison of two districts, one with high‐ and one with low‐extractive capacity. I find that generalised trust can explains some of the variation in extractive capacity across districts. The case studies trace the differences in trust and extractive capacity back to pre‐colonial rule; the better performing district having had centralised rule, a tradition of tax‐payment and a higher degree of social cohesion, while the poorer performing district had a more fragmented and less cohesive history of governance. The article thus points to the importance of understanding institutional path dependencies when assessing the feasibility of reform. Copyright © 2009 John Wiley & Sons, Ltd.
Functional water‐soluble polymers: polymer–metal ion removal and biocide properties
Authors: Rivas Bernabé L , Pereira Eduardo , Maureira Antonio
Published: July 2009

Water‐soluble polymers have attracted much interest due to their potential applications in environmental protection engineering to remove harmful pollutants and in biomedicine in the areas of tissue engineering, within‐body implants or other medical devices, artificial organ prostheses, ophthalmology, dentistry, bone repair, and so on. In this review, particular emphasis is given to the ability of water‐soluble polymers with amine, amide, carboxylic acid, hydroxyl and sulfonic acid functional groups to remove metal ions by means of the liquid‐phase polymer‐based retention (LPR) technique that combines the use of water‐soluble polymers and ultrafiltration membranes. The second part is dedicated to showing the potential application of functional water‐soluble polymers and their polymer–metal complexes as biocides for various bacteria. These polymers and polymer–metal complexes show an efficient bactericide activity, especially to Gram‐negative bacteria, Staphylococcus aureus reaching concentrations lower than 4 µg mL−1. This activity depends on polymer size, type of metal ion, contact time and concentration of polymer and metal ion. The discussion reveals that in the case of the LPR process the efficiency of metal ion removal depends strongly on the type of polymer functional group and the feed pH value. In general, two mechanisms of ion entrapment are suggested: complex formation and electrostatic interaction. In the case of the medical use of water‐soluble polymers and their complexes with metal ions, the review documents the unique bactericide properties of the investigated species. The polymer‐metal ion complexes show a reduced genotoxic activity compared with free metal ions. Copyright © 2009 Society of Chemical Industry
Prevalence of eating disturbance and body image dissatisfaction in young girls: An examination of the variance across racial and socioeconomic groups
Authors: DeLeel Marissa L. , Hughes Tammy L. , Miller Jeffrey A. , Hipwell Alison , Theodore Lea A.
Published: July 2009

Eating disorder research has predominantly focused on White adolescent females. More recent research suggests that eating disorders occur in various racial and age groups. The current study examines prevalence and stability of body image dissatisfaction and eating disturbance in 9‐ and 10‐year‐old girls and whether there is variability by racial group or socioeconomic status (SES). Five hundred eighty‐one girls completed the Children's Eating Attitude Test (ChEAT) and the Body Image Measure (BIM). Results showed that 11% of the sample scored in the Anorexic range at age 9 and about 7% at age 10. When examining body image, 35% of the sample at age 9 and 38% at age 10 selected Ideal Figures that were smaller than their Real Figures on the BIM. There was a significant difference between the racial groups in their reports of eating disturbance, but not body image dissatisfaction. Specifically, the Minority group had higher eating disturbance scores on average at ages 9 and 10 when compared to the White group. SES did not account for eating disturbance or body image dissatisfaction. These results challenge the maxim that eating disturbance and body image dissatisfaction occur primarily in White females from middle and upper SES populations. © 2009 Wiley Periodicals, Inc.
A whisper from the silent lung zone
Authors: Aljassim Fatma , Robinson Paul D. , Sigurs Nele , Gustafsson Per M.
Published: July 2009

Multiple breath inert gas washout (MBW) is now regarded as “an insightful, sound, and useful tool to explore the lung and its response to injury in all of its compartments”. We describe the important finding of pronounced intra‐acinar airways response to indirect challenge testing, detected using MBW but missed by spirometry, in an adolescent with evidence of airway inflammation, and a background of severe respiratory syncytial virus (RSV) infection as an infant. These tests were performed as part of an 18‐year follow up of a cohort with severe RSV infection (requiring hospitalization) in the first year of life, and has previously reported significantly higher rates of symptoms of allergic asthma and other features of atopic disease at 13 years in comparison to age matched controls. Small airway dysfunction and ventilation inhomogeneity have emerged as important features of early respiratory disease processes, and this case report provides further evidence supporting its important role in reactive airways disease. Pediatr Pulmonol. 2009; 44:829–832. © 2009 Wiley‐Liss, Inc.
Overexpression of Zip‐2 mRNA in the leukocytes of asthmatic infants
Authors: Xu Tong‐fu , Wang Xiao‐lei , Yang Jin‐zhi , Hu Xiao‐yan , Wu Wei‐fang , Guo Lu , Kang Lu‐dong , Zhang Lian‐ying
Published: July 2009

The increase in prevalence of asthma is strongly dependent on environmental factors, including foods. Significant decreases in the intake of dietary zinc may be an important contributing factor to the increasing incidence of asthma. As zinc can not passively diffuse across cell membranes, specific zinc transporters are required for zinc influx and efflux. There are two identified gene families involved in zinc homeostasis, ZnT transporters and ZIP transporters. In this study, we aimed to investigate the expression of these zinc transporters mRNA in the leukocytes of asthmatic infants. Asthmatic infants (n = 9) and healthy infants (n = 9) were included in this study. Five zinc transporters were chosen: ZnT‐1, ZnT‐3, ZnT‐5, ZIP‐1, and ZIP‐2. Levels of zinc were determined in serum and expression of zinc transporters mRNA were measured. Serum zinc levels were significantly lower in asthmatic infants (P < 0.01); Expression of ZnT‐1, ZnT‐3, ZnT‐5, ZIP‐1 mRNA were not significantly different between two groups, but expression of ZIP‐2 mRNA was significantly higher (P < 0.01) in the asthmatic group than the control group. In conclusion, overexpression of ZIP‐2 mRNA was found in the leukocytes of asthmatic infants. Pediatr Pulmonol. 2009; 44:763–767. © 2009 Wiley‐Liss, Inc.
Ionic determinants of exhaled breath condensate pH before and after exercise in adolescent athletes
Authors: Greenwald Roby , Ferdinands Jill M. , Teague W. Gerald
Published: July 2009

Background

The pH of exhaled breath condensate (EBC) of adolescent athletes engaged in vigorous physical activity is low compared to healthy controls; however, the ionic determinants of EBC pH and the acute effects of exercise on those determinants have not been definitively established.

Objectives

This study had two purposes: (1) to identify the ionic composition of EBC before and after exercise, and (2) to examine the effects of sample deaeration on EBC pH and composition.

Methods

EBC ionic composition was determined by ion chromatography and correlated with pH measured before and after deaeration. Bicarbonate concentration was calculated from the ion balance of other measured species and pH.

Results

EBC pH displayed a bimodal distribution, included values lower than expected for healthy individuals, and was correlated exclusively with volatile species, namely ammonia (mean concentration = 215 µM) and acetic (31.7 µM) and propionic acids (10.0 µM). Following exercise, raw EBC pH and ammonia concentration increased while propionic acid concentration fell. Following deaeration, EBC pH increased by one unit on average; however, the pH of samples with unusually low pH did not change significantly, and the concentrations of several ionic species were altered in a manner that cannot be explained in terms of volatility.

Conclusions

We conclude that in healthy adolescents, exercise results in an acute increase in raw EBC pH in association with an increase in ammonium and a decrease in propionate concentration. Since exercise increases systemic ammonia and urea (which is hydrolyzed by oral bacteria to form ammonia), we propose that the likely source of these changes is gas‐phase diffusion from epithelial and oral surface liquids and to a lesser extent, from pulmonary circulation. Pediatr Pulmonol. 2009; 44:768–777. © 2009 Wiley‐Liss, Inc.
The effects of racemic albuterol versus levalbuterol in very low birth weight infants
Authors: Mhanna Maroun J. , Patel Jigisha S. , Patel Swati , Cohn Robert
Published: July 2009

Bronchodilators have been used in premature infants. Levalbuterol (LEV) an R‐isomer of Albuterol has fewer hemodynamic side effects than Racemic Albuterol (RAC) in adults and children. In a retrospective study we sought to investigate the effects of LEV (0.31 mg) versus RAC (1.25 mg) in very low‐birth weight infants (VLBW) who were treated with a beta‐2 agonist for ≥2 weeks. Medical records (between January 2001 and December 2006) were reviewed for patients' demographics, medications use, hemodynamic and respiratory parameters, hypokalemia and hyperglycemia. Among 811 VLBW infants who were admitted to our NICU, 16 infants received RAC and 31 infants received LEV for ≥2 weeks. Infants who received RAC were younger, smaller, and received less Ipratropium Bromide (IB) than infants who received LEV [26.1 ± 1.2 weeks vs. 28.1 ± 3.7 weeks (P = 0.01), 817 ± 211 g vs. 1,127 ± 589 g (P = 0.01) and 2/16 (12%) vs. 15/31 (48%; P = 0.01); respectively]. In infants treated exclusively with RAC or LEV without IB, mean arterial blood pressures were lower in the RAC (n = 14) than the LEV group (n = 16, P = 0.05 by general linear model with repeated measures); however there were no differences in daily heart rates, oxygen supplementations, oxygen saturations, or respiratory rates. Also there were no differences between the two groups in hypokalemia or hyperglycemia. We conclude that LEV at a dose of 0.31 mg might have an indication in VLBW infants who are at risk for hemodynamic instability. Pediatr Pulmonol. 2009; 44:778–783. © 2009 Wiley‐Liss, Inc.
Influence of ventilatory settings on exhaled nitric oxide during high frequency oscillatory ventilation
Authors: Yuh Yeong‐Seng , Hua Yi‐Ming
Published: July 2009

Nitric oxide (NO), which is produced in the lower airways, diffuses from cells into the air space and can be measured in exhaled air. The influence of high frequency oscillatory ventilation on the production of exhaled NO (eNO) has not been thoroughly studied. The objectives of this study are to establish an animal model for evaluation of lower airway NO and to evaluate settings in terms of frequency, mean airway pressure (MAP), amplitude pressure (amplitude), and inspiratory time ratio (tI/tE) during high frequency oscillatory ventilation on the production of eNO. An observational animal study was performed on 12 female New Zealand White rabbits, which were anesthetized, tracheotomized and ventilated using a SensorMedics 3100A HFOV ventilator (SM3100A). The concentration of NO in exhaled gas was measured by chemiluminescence continuously from the nose and the side hole of the adaptor of endotracheal tube. The individual effects of the respiratory settings were evaluated. The results were analyzed by paired t‐test or by the generalized estimating equation method. We found that the lower airway was the main source of the eNO, that amplitude, MAP, and tI/tE were positively correlated with the level of eNO and that frequency was negatively correlated with the level of eNO. These findings fit the stretch theory for the production of endogenous NO. Monitoring of eNO during HFOV may provide insights into lung mechanics and ventilation efficiency and be used in the future as a guide during clinical practice. Pediatr Pulmonol. 2009; 44:800–805. © 2009 Wiley‐Liss, Inc.
Design of potent 9‐mer antimicrobial peptide analogs of protaetiamycine and investigation of mechanism of antimicrobial action
Authors: Shin Soyoung , Kim Jin‐Kyoung , Lee Jee‐Young , Jung Ki‐Woong , Hwang Jae‐Sam , Lee Juneyoung , Lee Dong Gun , Kim Iksoo , Shin Song Yub , Kim Yangmee
Published: July 2009

Protaetiamycine is an insect defensin, a naturally occurring 43‐amino‐acid‐residue antimicrobial peptide derived from the larvae of the beetle Protaetia brevitarsis. In a previous work that aimed at developing short antibiotic peptides, we designed 9‐mer peptide analogs of protaetiamycine. Among them, RLWLAIGRG‐NH2 showed good antifungal activity against Candida albicans. In this study, we designed four 9‐mer peptide analogs based on the sequence of RLWLAIGRG‐NH2, in which Gly or Ile was substituted with Arg, Lys, or Trp to optimize the balance between the hydrophobicity and cationicity of the peptides and to increase bacterial cell selectivity. We measured their toxicity to bacteria and mammalian cells as well as their ability to permeabilize model phospholipid membranes. Substitution of Arg for Gly9 at the C‐terminus (9Pbw1) resulted in two‐ to fourfold improvement in antibacterial activity. Further substitution of Gly7 with Lys (9Pbw2 and 9Pbw4) caused four‐ to eightfold improvement in the antibacterial activity without increase in cytotoxocity, while substitution of Gly7 with Trp (9Pbw3) increased cytotoxicity as well as antibacterial activity. The peptides 9Pbw2 and 9Pbw4 with the highest bacterial cell selectivity were not effective in depolarizing the membrane of Staphylococcus aureus cytoplasmic membranes and showed almost no leakage of a fluorescent dye entrapped within the vesicles. Gel‐retardation experiments indicated that 9Pbw2 and 9Pbw4 inhibited the migration of DNA at concentrations >20 µM. Three positively charged residues at the C‐terminus in 9Pbw2 and 9Pbw4 may facilitate effective penetration into the negatively charged phospholipid membrane of bacteria. The results obtained in this study suggest that the bactericidal action of our potent antibacterial peptides, namely 9Pbw2 and 9Pbw4, may be attributed to the inhibition of the functions of intracellular components after penetration of the bacterial cell membrane. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Critical percolation on random regular graphs
Authors: Nachmias Asaf , Peres Yuval
Published: July 2009

The behavior of the random graph G(n,p) around the critical probability pc = $ {1 \over n} $ is well understood. When p = (1 + O(n1/3))pc the components are roughly of size n2/3 and converge, when scaled by n−2/3, to excursion lengths of a Brownian motion with parabolic drift. In particular, in this regime, they are not concentrated. When p = (1 ‐ ϵ(n))pc with ϵ(n)n1/3 →∞ (the subcritical regime) the largest component is concentrated around 2ϵ−2 log(ϵ3n). When p = (1 + ϵ(n))pc with ϵ(n)n1/3 →∞ (the supercritical regime), the largest component is concentrated around 2ϵn and a duality principle holds: other component sizes are distributed as in the subcritical regime.

Itai Benjamini asked whether the same phenomenon occurs in a random d‐regular graph. Some results in this direction were obtained by (Pittel, Ann probab 36 (2008) 1359–1389). In this work, we give a complete affirmative answer, showing that the same limiting behavior (with suitable d dependent factors in the non‐critical regimes) extends to random d‐regular graphs. © 2009 Wiley Periodicals, Inc. Random Struct. Alg., 2010
Estimating variance parameters from multivariate normal variables subject to limit of detection: MLE, REML, or Bayesian approaches?
Authors: Nie Lei , Chu Haitao , Feng Shibao
Published: July 2009

Likelihood‐based approaches, which naturally incorporate left censoring due to limit of detection, are commonly utilized to analyze censored multivariate normal data. However, the maximum likelihood estimator (MLE) typically underestimates variance parameters. The restricted maximum likelihood estimator (REML), which corrects the underestimation of variance parameters, cannot be easily extended to analyze censored multivariate normal data. In the light of the connection between the REML and a Bayesian approach discovered in 1974 by Dr Harville, this paper describes a Bayesian approach to censored multivariate normal data. This Bayesian approach is justified through its link to the REML via Laplace's approximation and its performance is evaluated through a simulation study. We consider the Bayesian approach as a valuable alternative because it yields less biased variance parameter estimates than the MLE, and because a solid REML is technically difficult when data are left censored. Copyright © 2009 John Wiley & Sons, Ltd.
Mesoporous‐Silica‐Coated Up‐Conversion Fluorescent Nanoparticles for Photodynamic Therapy
Authors: Qian Hai Sheng , Guo Hui Chen , Ho Paul Chi‐Lui , Mahendran Ratha , Zhang Yong
Published: July 2009

Near‐infrared (NIR)‐to‐visible up‐conversion fluorescent nanoparticles have potential to be used for photodynamic therapy (PDT) in deep tissue because NIR light can penetrate thick tissue due to weak absorption in the optical window. Here a uniform layer of mesoporous silica is coated onto NaYF4 up‐converting nanocrystals, with a large surface area of ≈770 m2 g−1 and an average pore size of 2 nm. A photosensitizer, zinc phthalocyanine, is incorporated into the mesoporous silica. Upon excitation by a NIR laser, the nanocrystals convert NIR light to visible light, which further activates the photosensitizer to release reactive singlet oxygen to kill cancer cells. The photosensitizer encapsulated in mesoporous silica is protected from degradation in the harsh biological environment. It is demonstrated that the photosensitizers loaded into the porous silica shell of the nanoparticles are not released out of the silica while they continuously produce singlet oxygen upon excitation by a NIR laser. The nanoparticles are reusable as the photosensitizers encapsulated in the silica are removed by soaking in ethanol.
Influence of Gluten and Gum Additives and Cryogenic Treatment on Some Properties and Morphology of Wheat Starch Complex Gels
Authors: Wasserman Luybov A. , Vasil'ev Viktor G. , Motyakin Michael V. , Blaszchak Wioletta , Fornal Jozef , Damshkaln Liliya G. , Lozinsky Vladimir I. , Yuryev Vladimir P.
Published: July 2009

The influence of gums (guar and xanthan) and gluten additives on the physicochemical properties and structural features of wheat starch gels (8%, w/w) subjected to cryogenic treatment at various temperatures (−9°C, −20°C, −40°C) was studied. Shear modulus and breaking stress of the gels were measured, the gels' morphology was studied with optical microscopy and the local mobility of water in the gels was determined with ESR. The total concentration of polysaccharide additives did not exceed 1% (w/w), and a 65:35 (w/w) mixture of guar and xanthan gums proved to be the optimal additive, which caused a noticeable increase in rigidity and strength of the resulting complex gels. Shear modulus and breaking stress of the gels decreased with lowering the temperature of the cryogenic treatment. The heterogeneous morphology of thin sections of the gel samples was revealed via optical microscopy. ESR studies showed that the local mobility of water was much lower in the gels than in pure water.
Evaluation ofN‐benzyl‐N‐[11C]methyl‐2‐ (7‐methyl‐8‐oxo‐2‐phenyl‐7,8‐dihydro‐9H‐purin‐9‐yl)acetamide ([11C]DAC) as a novel translocator protein (18 kDa) radioligand in kainic acid‐lesioned rat
Authors: Yanamoto Kazuhiko , Yamasaki Tomoteru , Kumata Katsushi , Yui Joji , Odawara Chika , Kawamura Kazunori , Hatori Akiko , Inoue Osamu , Yamaguchi Masatoshi , Suzuki Kazutoshi , Zhang Ming‐Rong
Published: July 2009

The aim of this study was to evaluateN‐benzyl‐N‐[11C]methyl‐2‐(7‐methyl‐8‐oxo‐2‐phenyl‐7,8‐dihydro‐9H‐purin‐9‐yl)acetamide ([11C]DAC) as a new translocator protein (18 kDa) [TSPO, formerly known as the peripheral‐type benzodiazepine receptor (PBR)] positron emission tomography (PET) ligand in normal mice and unilateral kainic acid (KA)‐lesioned rats. DAC is a derivative of AC‐5216, which is a potent and selective PET ligand for the clinical investigation of TSPO. The binding affinity and selectivity of DAC for TSPO were similar to those of AC‐5216, and DAC was less lipophilic than AC‐5216. The distribution pattern of [11C]DAC was in agreement with TSPO distribution in rodents. No radioactive metabolite of [11C]DAC was found in the mouse brain, although it was metabolized rapidly in mouse plasma. Using small‐animal PET, we examined the in vivo binding of [11C]DAC for TSPO in KA‐lesioned rats. [11C]DAC and [11C]AC‐5216 exhibited similar brain uptake in the lesioned and nonlesioned striatum, respectively. The binding of [11C]DAC to TSPO was increased significantly in the lesioned striatum, and [11C]DAC showed good contrast between the lesioned and nonlesioned striatum (the maximum ratio was about threefold). In displacement experiments, the uptake of [11C]DAC in the lesioned striatum was eventually blocked using an excess of either unlabeled DAC or PK11195 injected. [11C]DAC had high in vivo specific binding to TSPO in the injured rat brain. Therefore, [11C]DAC is a useful PET ligand for TSPO imaging, and its specific binding to TSPO is suitable as a new biomarker for brain injury. Synapse 63:961–971, 2009. © 2009 Wiley‐Liss, Inc.
Endocannabinoid modulation of amphetamine sensitization is disrupted in a rodent model of lesion‐induced dopamine dysregulation
Authors: Eisenstein Sarah A. , Holmes Philip V. , Hohmann Andrea G.
Published: July 2009

We tested the hypothesis that increased dopaminergic sensitivity induced by olfactory bulbectomy is mediated by dysregulation of endocannabinoid signaling. Bilateral olfactory bulbectomy induces behavioral and neurobiological symptomatology related to increased dopaminergic sensitivity. Rats underwent olfactory bulbectomy or sham operations and were assessed 2 weeks later in two tests of hyperdopaminergic responsivity: locomotor response to novelty and locomotor sensitization to amphetamine. Amphetamine (1 mg/kg i.p.) was administered to rats once daily for 8 consecutive days to induce locomotor sensitization. URB597, an inhibitor of the anandamide hydrolyzing enzyme fatty‐acid amide hydrolase (FAAH), was administered daily (0.3 mg/kg i.p.) to sham and olfactory bulbectomized (OBX) rats to investigate the impact of FAAH inhibition on locomotor sensitization to amphetamine. Pharmacological specificity was evaluated with the CB1 antagonist/inverse agonist rimonabant (1 mg/kg i.p). OBX rats exhibited heightened locomotor activity in response to exposure either to a novel open field or to amphetamine administration relative to sham‐operated rats. URB597 produced a CB1‐mediated attenuation of amphetamine‐induced locomotor sensitization in sham‐operated rats. By contrast, URB597 failed to inhibit amphetamine sensitization in OBX rats. The present results demonstrate that enhanced endocannabinoid transmission attenuates development of amphetamine sensitization in intact animals but not in animals with OBX‐induced dopaminergic dysfunction. Our data collectively suggest that the endocannabinoid system is compromised in olfactory bulbectomized rats. Synapse 63:941–950, 2009. © 2009 Wiley‐Liss, Inc.
Differential corticosteroid receptor regulation of mesoaccumbens dopamine efflux during the peak and nadir of the circadian rhythm: A molecular equilibrium in the midbrain?
Authors: Tye Susannah J. , Miller Anthony D. , Blaha Charles D.
Published: July 2009

Corticosteroid receptor modulation of mesoaccumbens dopamine neurotransmission is believed to be a key neurobiological mechanism mediating the effects of stress in addiction. Importantly, nucleus accumbens (NAc) subregions (core and shell) are reported to respond differentially to fluctuating basal levels of glucocorticoids, with dopaminergic responses in the core of the NAc being somewhat impervious to fluctuating levels of glucocorticoids relative to the shell. To investigate the corticosteroid receptor mechanisms mediating basal dopamine efflux in the core of the NAc, we have used chronoamperometry in combination with stearate‐modified graphite paste electrodes in urethane anesthetized male Long–Evans rats during the peak and nadir of the circadian cycle. Blockade of ventral tegmental area low‐affinity glucocorticoid (GR) or high‐affinity mineralocorticoid (MR) receptors with mifepristone (1 μg/μl) or spironolactone (0.2 μg/μl), respectively, indicated that endogenous phase‐dependent corticosteroid receptor activation (GRs during peak; MRs during nadir) facilitated extracellular NAc dopamine efflux. Conversely, the alternate receptor's actions appeared inhibitory at these time points (MRs during peak; GRs during nadir). Pharmacological activation of either the GR or MR with corticosterone (2 μg/μl) or aldosterone (0.2 μg/μl), respectively, potentiated NAc dopamine efflux, irrespective of circadian phase. Together, these data suggest that dominant corticosteroid receptor activation stimulates tonic mesoaccumbens dopamine transmission, enabling MRs and GRs to differentially maintain basal NAc dopamine release over the course of the circadian cycle. This points to an important molecular mechanism through which relatively stable NAc core dopamine extracellular levels could be maintained in the face of fluctuating corticosterone circadian rhythms. Synapse 63:982–990, 2009. © 2009 Wiley‐Liss, Inc.