bluuebunny/crossref_metadata_2025 huggingface dataset:
Engineered Si wafers: On the role of oxide heterostructures as buffers for the integration of alternative semiconductors
Authors: Schroeder T. , Giussani A. , Dabrowski J. , Zaumseil P. , Müssig H.‐J. , Seifarth O. , Storck P.
Published: January 2009

Engineered Si wafer systems present an important materials science approach to further improve the performance of Si‐based micro‐ and nanoelectronics. This is due to the potential to integrate alternative semiconductor layers on the mature Si wafer technology platform which are otherwise too expensive or even impossible to grow in bulk form in the required quality and quantity. Ge is attracting increasing research interest because it is for example a promising material for high mobility channel CMOS technologies as well as a mediator material to achieve the manufacturing of III‐V/Si hybrid devices. The integration of Ge on Si wafers is today either achieved by a combination of layer transfer and wafer bonding techniques or by a sequence of subsequent, epitaxial thin film deposition growth steps. In the latter case, the traditional approach to integrate Ge layers of low defect densities is given by the use of compositionally graded SiGe heterostructures. As this approach suffers however from required SiGe buffer thicknesses on the micrometer scale, making integrated circuit processing difficult, research on the development of innovative buffer heteroepitaxy approaches is intensively pursued. A new interesting class of buffer materials with a high degree of flexibility is given by oxide heterostructures. Using the integration of single crystalline Si and Ge on the Si(111) material platform via oxide heterostructures as an example, the flexibility of engineered oxide heterostructures to control important epitaxy parameters is demonstrated. In this study, epitaxial Si(111) and Ge(111) layers were grown on cubic Y2O3(111)/cubic Pr2O3(111)/Si(111) and Pr2O3(111)/Si(111) support systems, respectively. The structural properties of the Si‐on‐Insulator (SOI) and Ge‐on‐Insulator (GOI) heterostructures were characterized in detail by a combination of laboratory‐ and synchrotron‐based methods. As main result, both the epitaxial Si(111) and Ge(111) films were shown to be atomically smooth and single crystalline (i.e. free of stacking twins). Defect engineering approaches need to be applied in future to reduce stacking faults (e.g. microtwins) which are identified as the major defect mechanism in the epitaxial Si(111) and Ge(111) films. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystalline silicon for photovoltaics
Authors: Kaden Thomas , Würzner Sindy , Dreckschmidt Felix , Möller Hans‐Joachim
Published: January 2009

Crystalline silicon is currently the basis of about 95% of all solar cells commercially available. Multicrystalline silicon makes up over the half of this amount. The complex defect occurrence and interaction of defects in this material offers a wide field of research and a high potential for material improvement. Extended lattice defects such as dislocations and grain boundaries are important as recombination and storage centres for metallic impurities. Their control is essential to obtain high efficiencies of the solar cell. Important parameters for the assessment of the final efficiency of the solar cells are the distribution and structure of the defects and their impact on the lifetime of minority charge carriers. The current understanding of the nucleation mechanisms of the most important defects during crystal growth will be described. Interaction processes between mobile impurities and extended defects are important for the recombination activity. Measurements of the recombination behaviour and the contamination level will be presented. Effects on the solar cell efficiency shall be discussed. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Wafer bonding in silicon electronics
Authors: Reiche Manfred
Published: January 2009

Semiconductor wafer bonding offers a new degree of freedom in the design of material combinations without the common restrictions of the structure of the materials bonded. It is already an established method for the industrial production of advanced substrates (SOI) applied as basic material in high‐performance device fabrication. SOI, i.e. a thin device layer on an insulator, is a promising concept for further device developments. The advantages of SOI can be combined with mobility enhancing materials such as strained silicon (SSOI) or germanium on insulator (GOI). The bonding process is not limited to a certain wafer diameter and is applicable to different material combinations which are important to integrate different functions on a chip (system on a chip, SoC). (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High power AlGaN/GaN HFETs on 4 inch Si substrates
Authors: Ikeda Nariaki , Kaya Syuusuke , Li Jiang , Sato Yoshihiro , Kokawa Takuya , Kato Sadahiro
Published: January 2009

In this paper, we successfully demonstrate an AlGaN/GaN HFET with a high breakdown voltage on 4‐inch Si substrates. In order to obtain the high breakdown voltage and to improve the crystalline quality of GaN layers, a thick GaN epitaxial layer including a buffer layer was grown. The breakdown voltage and the maximum drain current were achieved to be over 1.3 kV and 120 A, respectively. Furthermore, the suppression of a current collapse phenomenon was examined. The on‐resistance was not significantly increased up to a high drain off‐bias‐stress of 900 V. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature‐dependent droop of electroluminescence efficiency in blue (In,Ga)N quantum‐well diodes
Authors: Fujiwara Kenzo , Jimi Hiroyuki , Kaneda Kei
Published: January 2009

Temperature‐dependent electroluminescence (EL) intensity of a blue (In,Ga)N single quantum‐well diode has been extensively investigated as a function of current between 2 nA and 10 mA at 20‐300 K. At 300 K the EL external quantum efficiency (ηex) shows a maximum at a current density of ∼1 A/cm2 and droops under higher injection. However, the current density for the ηex maximum significantly decreases with decreasing temperature, for example, to ∼5 × 10–4 A/cm2 at 20 K, with improved maximum EL efficiency due to reduced nonradiative recombination. This low‐temperature enhancement of the ηex droop at lower injection indicates that the droop phenomena is not involved with high‐density carrier effects like Auger nonradiative recombination, but rather linked with the carrier escape under high forward bias conditions due to the presence of internal piezo‐fields in (In,Ga)N quantum‐well heterostructures. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Selective growth of GaN nanodots and nanostripes on 6H‐SiC substrates by metal organic vapor phase epitaxy
Authors: Goh W. H. , Martin J. , Ould‐Saad S. , Gautier S. , Sirenko A. A. , Martinez A. , Le Gratiet L. , Ramdane A. , Maloufi N. , Ougazzaden A.
Published: January 2009

GaN nanodots and nanostripes with smooth sidewall surfaces have been selectively grown on 6H‐SiC substrates by metal organic vapor phase epitaxy. By varying the growth reactor pressure, we have been able to grow either isolated nanostructures or laterally overgrown structures. As confirmed by the Raman scattering and X‐ray diffraction techniques, the nanostructures have no influence of step bunching that occurs in the unmasked area of the continuous GaN film. The frequency shift of the E2 optical phonons shows that the residual strain in the nanostripes is relaxed compared to the continuous GaN film. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Proposal and simulated results of a normally off AlGaN/GaN HFET structure with a charged floating gate
Authors: Hasegawa Fumio , Kambayashi Hiroshi , Li Jiang , Ikeda Nariaki , Nomura Takehiko , Kato Sadahiro , Yoshida Seiko
Published: January 2009

A normally off AlGaN/GaN Hetero‐junction Field Effect Transistor (HFET) structure is proposed. Two dimensional electron gas (2DEG) of more than 1 × 1013 cm–2, which a AlGaN/GaN HFET generally has, can be compensated completely by the negative charge in a floating gate or in a SiO2 layer on the AlGaN. Computer simulation showed that the threshold voltage was shifted from ‐3 V to ‐15 V with 20 nm SiO2 layer between the control gate and the AlGaN layer, but it was also shifted to +5V with 5 × 1013 cm–2 electrons (negative charge) in the middle of the SiO2 layer (a floating gate) or minus ions in the SiO2 layer itself. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Epitaxial design of 475 nm InGaN laser diodes with reduced wavelength shift
Authors: Queren Désirée , Avramescu Adrian , Schillgalies Marc , Peter Matthias , Meyer Tobias , Brüderl Georg , Lutgen Stephan , Strauß Uwe
Published: January 2009

We have analyzed the quantum well stability of blue‐green emitting laser diodes grown on c ‐plane GaN substrates. Different parameters such as the material composition of the surrounding layers of the quantum well and the number of quantum wells were varied. We observed a strong influence of the barrier material composition (AlGaN, GaN, InGaN) on the quality of In rich quantum wells. Our preferred barrier material is GaN. In contrast InGaN barriers result in a higher defect density of 9.6 × 106 cm–2 in the quantum well whereas GaN barriers show a defect density of 1.8 × 106 cm–2. High indium content quantum wells with good crystalline quality were grown by improving the structure of the complete active region. Further enhancement could be achieved by using a double quantum well structure instead of a single quantum well structure. This offers the advantage that the wavelength shift is strongly reduced as a result of the lower current density in each quantum well. With our improvements we could realize laser diodes emitting at 475 nm with threshold current densities of 12 kA/cm2 and a slope efficiency of 500 mW/A. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resonant coupling between a gold‐nanosphere plasmon and localized excitons in InGaN
Authors: Toropov A. A. , Shubina T. V. , Jmerik V. N. , Ivanov S. V. , Ogawa Y. , Minami F.
Published: January 2009

We report on site‐selective enhancement of the emission of localized excitons in an In0.3Ga0.7N solid alloy, induced by a gold nanoparticle attached to an AFM probe and placed at the near‐field distance of the film surface. The InGaN films with a specific rough surface were grown on a GaN buffer layer by molecular beam epitaxy. Most of the amplifying effect is attributed to the local enhancement of the spontaneous emission recombination rate due to the coupling of the exciton emission dipole to the macroscopic dipole in the spheroidal gold nanoparticle at the frequency of the electronic plasma resonance. At low temperatures we demonstrate drastic narrowing of the photoluminescence line due to the selective enhancement of a part of the inhomogeneously broadened emission spectrum by affecting only a limited number of localized excitons. The presented technique allows relatively easy mapping of the distribution of localized excitons in solid alloys and nanostructures with the resolution below the diffraction limit and represents a way to extract and amplify the emission of single quantum emitters (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Measurement of misorientation of AlN layer grown on (111)Si for freestanding substrate
Authors: Saito K. , Tajima J. , Kumagai Y. , Ishizuki M. , Takada K. , Morioka H. , Koukitu A.
Published: January 2009

A novel technique for misorientation determination based on energy dispersive X‐ray diffraction is introduced. The energy dispersive diffractometer equips with a silicon drift detector as a energy dispersive detector and a micro focus air cooled X‐ray tube as a source. The diffractometer has advantages in speed of measurement and alignment of sample compared with conventional angular dispersive diffractometer. Dependence of misorientation of AlN layers on misorientation angle and direction of (111) Si starting substrates were investigated by this method. It is found that the AlN has (0001) orientation and the (0001) plane is tilted when the film thickness is thin. Moreover, it is shown that the tilt becomes smaller with increasing the film thickness. The atomic force microscopy (AFM) showed clear difference in surface morphology of obtained AlN layer depending on misorientation direction of Si substrate. The AlN film grown on (111) Si with 1 degree misorientation angle toward [$ \bar 1 \bar 1 2 $] showed the best step and terrace structure compared with those grown on that having larger than 1 degree misorientation angle. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Surface changes by GaN photoelectrochemical treatment using various electrolytes with and without C2H5OH
Authors: Fujii Katsushi , Sato Keiichi , Kato Takashi , Koike Kayo , Yao Takafumi
Published: January 2009

The surface changes of n‐type GaN during photoelectrochemical treatment were investigated by not only electrochemical measurement but also photoluminescence (PL). The electrolytes used were H2SO4, Na2SO4, and NaOH with and without C2H5OH in order to clarify the reaction difference. The intensity oscillations of deep PL peaks decreased with increasing surface roughness. The D0X peak shift with strain release by the surface roughened were also observed. The surface treated using Na2SO4 with/without C2H5OH were oxidized and caused new PL peaks related to the surface defects. All of the surfaces treated with C2H5OH were observed much less change. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Substituent effect on intramolecular hydrogen bonding in 2‐hydroxybenzaldehyde
Authors: Ebrahimi A. , Habibi S. M. , Neyband R. S.
Published: January 2009

The effect of some substituents on intramolecular hydrogen bonding of 5‐X‐2‐hydroxybenzaldehyde (5‐X‐2‐HBA) has been studied by B3LYP and MP2 methods using 6‐311++G** and AUG‐cc‐PVTZ basis sets. The relationship between hydrogen bond energyEHBand electron donation (or withdrawal) of substituents has been investigated. An approximately good linear relationship has been detected between Hammett coefficients and hydrogen bond formation energy (R2= 0.98). Herein, population analysis has been performed by atoms in molecules (AIM) and natural bond orbital (NBO) methods. The results of AIM and NBO analyses are in a good agreement with calculated energy values. Furthermore, correlation between ring aromaticity and hydrogen bonding has been investigated by nucleus‐independent chemical shift (NICS) at GIAO/B3LYP/6‐311++G** level of theory. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Use of activated graphitized carbon chips for liquid chromatography/mass spectrometric and tandem mass spectrometric analysis of tryptic glycopeptides
Authors: Alley William R. , Mechref Yehia , Novotny Milos V.
Published: January 2009

Protein glycosylation has a significant medical importance as changes in glycosylation patterns have been associated with a number of diseases. Therefore, monitoring potential changes in glycan profiles, and the microheterogeneities associated with glycosylation sites, are becoming increasingly important in the search for disease biomarkers. Highly efficient separations and sensitive methods must be developed to effectively monitor changes in the glycoproteome. These methods must not discriminate against hydrophobic or hydrophilic analytes. The use of activated graphitized carbon as a desalting media and a stationary phase for the purification and the separation of glycans, and as a stationary phase for the separation of small glycopeptides, has previously been reported. Here, we describe the use of activated graphitized carbon as a stationary phase for the separation of hydrophilic tryptic glycopeptides, employing a chip‐based liquid chromatographic (LC) system. The capabilities of both activated graphitized carbon and C18 LC chips for the characterization of the glycopeptides appeared to be comparable. Adequate retention time reproducibility was achieved for both packing types in the chip format. However, hydrophilic glycopeptides were preferentially retained on the activated graphitized carbon chip, thus allowing the identification of hydrophilic glycopeptides which were not effectively retained on C18 chips. On the other hand, hydrophobic glycopeptides were better retained on C18 chips. Characterization of the glycosylation sites of glycoproteins possessing both hydrophilic and hydrophobic glycopeptides is comprehensively achieved using both media. This is feasible considering the limited amount of sample required per analysis (<1 pmol). The performance of both media also appeared comparable when analyzing a four‐protein mixture. Similar sequence coverage and MASCOT ion scores were observed for all proteins when using either stationary phase. Copyright © 2009 John Wiley & Sons, Ltd.
Periphyton and invertebrate response to wood placement in large pacific coastal rivers
Authors: Coe Holly J. , Kiffney Peter M. , Pess George R. , Kloehn Kris K. , McHenry Michael L.
Published: January 2009

Wood abundance in aquatic systems has been dramatically reduced compared to historical levels due to anthropogenic activities that led to wood removal and stream simplification. As a result, reintroduction of wood to aquatic systems is now a widely used and relatively well‐studied restoration technique for increasing habitat complexity. Although stream periphyton (biofilm) and invertebrates serve as food sources for a variety of predators including fish, birds and bats, data on how lower trophic levels respond to wood placement are relatively scarce. The purpose of this study was to test the hypothesis that periphyton biomass and aquatic invertebrate density were higher on Engineered Log Jams (ELJs) than on inorganic substrates in two large Pacific Northwest river systems. Among years and rivers, periphyton biomass and invertebrate densities were significantly higher on ELJs than on cobbles within the same reach. Invertebrate communities on ELJs were dominated by meiofauna (<500 µm), whereas cobbles were dominated by larger chironomids. We attribute these trophic level differences to substrate type, as we did not detect taxonomic differences between cobbles in reaches with and without ELJs. We show that adding wood to reaches with little or no naturally occurring wood increased overall habitat surface area and thereby the potential for increased productivity relative to reaches with low levels of wood. Finally, wood supports a unique community of invertebrates that are often overlooked in lotic system studies but may be contributing substantially to overall biological diversity. Published in 2009 by John Wiley & Sons, Ltd.
Verification-guided modelling of salience and cognitive load
Authors: Rukšėnas Rimvydas , Back Jonathan , Curzon Paul , Blandford Ann
Published: January 2009

Well-designed interfaces use procedural and sensory cues to increase the cognitive salience of appropriate actions. However, empirical studies suggest that cognitive load can influence the strength of those cues. We formalise the relationship between salience and cognitive load revealed by empirical data. We add these rules to our abstract cognitive architecture, based on higher-order logic and developed for the formal verification of usability properties. The interface of a fire engine dispatch task from the empirical studies is then formally modelled and verified. The outcomes of this verification and their comparison with the empirical data provide a way of assessing our salience and load rules. They also guide further iterative refinements of these rules. Furthermore, the juxtaposition of the outcomes of formal analysis and empirical studies suggests new experimental hypotheses, thus providing input to researchers in cognitive science.
Peasants into Syrians
Authors: Martin Kevin W.
Published: January 2009

Like much of the “developing world,” Syria experienced urban population growth at historically unprecedented rates in the 1950s. Such rapid urbanization, like all transformative historical phenomena, animates (and, to a certain extent, reifies) a host of dreams and anxieties in those who experience it. To get an inkling of how “Syrians”—as individuals, groups, or representatives of institutions—felt about these changes, one has to look beyond the ubiquitous and frequent pronouncements of intellectuals and government officials extolling the virtues of modernity and the liberating effects of science and technology.
Pensée 3: The Modernity of the Arabs
Authors: Halliday Fred
Published: January 2009

The study of Arab nationalism, and indeed of all nationalisms, is beset with particular problems. One is the imprecision of the main concepts involved, starting with the definition of nation. Another is the confusion, inherent in the very word “nationalism,” between two quite different objects of study—nationalism as a movement, as a social and political force, and nationalism as an ideology. The first allows objective, historical analyses of how a particular movement arose and developed in such and such a country, of the social groups that supported and/or opposed it, and, not least, of how states have sought to define and utilize it. The second is an aspiration, an ideological and normative claim, one with a strong tendency to control public debate; it has an inherent tendency to distort the history of the supposed “nation.” The special claims nationalists make for their particular nation cause a third problem: although modern history has yielded hundreds of cases of nationalism, as movement and ideology, nationalism occasions analysis that is singular, treating the nation in question as unique and avoiding comparison.
COMMENTS FROM AN AUTHOR: ENGAGING THE ARAB HUMAN DEVELOPMENT REPORT 2005 ON WOMEN
Authors: Jad Islah
Published: January 2009

I think it is safe to say that the Arab Human Development Report 2005 (AHDR 2005) was the first report to be criticized and even attacked by its own authors. Some contested not being “fully” the “owner” of the report because they were forced to share it with some “disappointing” partners; some attacked it for not fully representing their fundamentalist secular beliefs. Others showed their discontent with its theoretical incoherence and its clear neoliberal approach. These differing stands reflect the spectrum of conflicting views and approaches in the Arab world about women's issues; they also reflect the lack of a spirit of teamwork.
Psychosoziale «TANDEMGRUPPEN» 1Leuchtturmprojekt Demenz, Themenfeld 2 Evaluation von Versorgungsstrukturen/Frühe Erkrankungsphase.
Authors: Niemann-Mirmehdi Mechthild , Soellner Renate , Kalus Peter , Richert Annette , Heinz Andreas , Rapp Michael
Published: January 2009

Die Evaluationsstudie sozialtherapeutischer «Tandemgruppen» widmet sich der frühzeitigen wie langfristigen psychosozialen Unterstützung bei der Krankheits- und Alltagsbewältigung präsenil erkrankter Demenzpatienten und ihrer Angehörigen. Zentral ist hierbei die Analyse hemmender und fördernder Faktoren für die Wirksamkeit der parallel angebotenen psychosozialen Patienten- und Angehörigengruppen. Zielsetzungen, gleichermaßen für die Erkrankten wie für ihre Angehörigen, meist Ehe- und Lebenspartner, sind sozialen Rückhalt, Aktivierung, Wissenserwerb, einen schamfreien, enttabuisierenden Umgang mit der Erkrankung und den damit einhergehenden Belastungen zu fördern sowie einer Unter- und Fehlversorgung vorzubeugen. Die Ergebnisse dieser primär qualitativ angelegten Pilotstudie sollen zur flächendeckenden Implementierung psychosozialer Frühinterventionen, hier präsenil erkrankter Demenzpatienten, zur Förderung von mehr Lebensqualität in einem Handbuch zusammengefasst werden.
Qualifizierungsmaßnahmen zur Steigerung der Lebensqualität demenzkranker Menschen über eine Förderung der Kommunikation und Kooperation in der ambulanten Altenpflege (Quadem)
Authors: Haberstroh Julia , Ehret Sonja , Kruse Andreas , Schröder Johannes , Pantel Johannes
Published: January 2009

Im vorliegenden Beitrag wird das innovative Schulungskonzept Quadem vorgestellt. Das Projektvorhaben nutzt zwei wissenschaftlich evaluierte und in der Praxis bewährte Qualifizierungsmaßnahmen: 1. Tandem, Trainings für familiär, professionell und ehrenamtlich Pflegende zur Steigerung von sozialen Schlüsselkompetenzen, insbesondere der Kommunikations- und Kooperationsfähigkeiten sowie 2. THELIA, ein Programm zur Schulung ehrenamtlich und familiär Pflegender, das diese in die Lage versetzt, für demenzkranke Menschen zentrale Lebensthemen zu erkennen und in die alltägliche Versorgung zu integrieren. Durch die beiden Qualifizierungsmaßnahmen soll dazu beigetragen werden, dass die in die Pflege eines Demenzkranken involvierten Personen effektiver zusammenarbeiten und der Individualität Demenzkranker besser gerecht werden. Entsprechend sollte die von familiär und professionell Pflegenden erlebte Beanspruchung reduziert, das Sinnerleben von familiär, professionell und ehrenamtlich Pflegenden gestärkt und vor allem die Lebensqualität der in ambulanten Pflegesystemen versorgten Demenzkranken verbessert werden.
Pharmakotherapie bipolarer Störungen im Kindes- und Jugendalter
Authors: Vloet Jennifer A. , Hagenah Ulrich F.
Published: January 2009

Zusammenfassung: Hintergrund: Bipolare Störungen im Kindes- und Jugendalter sind seltene, aber ernste und oft zu weitreichenden Behinderungen in allen Lebensbereichen führende Erkrankungen. Im Zentrum der Behandlung steht die Pharmakotherapie, die über die Akutbehandlung hinaus meist mehrjährig als Rückfallprophylaxe fortgesetzt werden muss. Methodik: Durchgeführt wurde eine Medline-Recherche (Pubmed), mit der Suchstrategie: bipolar - mania - adolescents - early onset - pediatric onset - randomized - controlled trial - neuroleptics - antipsychotics - lithium - moodstabilizer. Ergebnisse: Trotz weit verbreiteter Anwendung von für das Erwachsenenalter etablierten Substanzen bei bipolar erkrankten Kindern und Jugendlichen existiert aktuell eine nur unzureichende Datenlage zur Wirksamkeit und Sicherheit der Anwendung in dieser Altersgruppe. Die Interpretation der Datenlage aus überwiegend offenen Studien wird durch die Kontroverse bezüglich der diagnostischen Validität bipolarer Störungen bei Kindern erschwert. Nebenwirkungen treten bei Kindern und Jugendlichen unter allen eingesetzten Substanzen häufiger und ausgeprägter auf als bei Erwachsenen und limitieren den Einsatz. Schlussfolgerungen: Auch wenn die vorliegenden Daten auf eine Wirksamkeit und ausreichende Verträglichkeit von atypischen Neuroleptika und Moodstabilizern in der Akutbehandlung von Kindern und Jugendlichen mit bipolarer Störung weisen, sind zusätzliche Placebo-kontrollierte Studien und Studien zur Langzeitbehandlung dringend erforderlich.
Impact Factors und Publikationszeitspannen kinder- und jugendpsychiatrischer Journals
Authors: Haberhausen Michael , Bachmann Christian
Published: January 2009

Zusammenfassung: Fragestellung: Der Impact Factor (IF) einer wissenschaftlichen Zeitschrift hat eine wichtige Bedeutung für die Überlegung eines Wissenschaftlers, seine Forschungsergebnisse dort zu publizieren. Ebenso ist die Publikationsspanne, d.h. die Zeit, die vom Einreichen eines Artikels bis zur endgültigen Publikation vergeht, für den Autor von Interesse. In der vorliegenden Arbeit wird deshalb eine Übersicht über IF und Publikationsspannen deutscher und internationaler kinder- und jugendpsychiatrischer Zeitschriften gegeben. Methodik: Es wurde eine Datenbankrecherche in den Journal Citation Reports hinsichtlich IF und IF-Entwicklung der einschlägigen kinder- und jugendpsychiatrischen Zeitschriften 2002-2007 sowie eine Per-Hand-Auswertung dieser Zeitschriften hinsichtlich der Publikationsspannen für das Jahr 2007 durchgeführt. Ergebnisse: Aktuell existieren neun kinder- und jugendpsychiatrische Fachzeitschriften, von denen acht über einen IF verfügen. Die Spannbreite der IF bewegt sich von 0,419 (Praxis der Kinderpsychologie und Kinderpsychiatrie) bis 4,655 (Journal of the American Academy of Child and Adolescent Psychiatry). Die Publikationsspannen betrugen zwischen 5,4 und 13,2 Monaten. Schlussfolgerungen: Obwohl die Kinder- und Jugendpsychiatrie als «kleines Fach» gilt, verfügt sie über Zeitschriften mit international konkurrenzfähigem IF. Die beiden deutschsprachigen Zeitschriften zeigen einen eher niedrigen IF. Die Publikationsspannen sind angemessen und könnten durch Online-Vorabpublikationen noch verkürzt werden.
ADHS bei Jungen im Kindesalter - Lebensqualität und Erziehungsverhalten
Authors: Schreyer Ina , Hampel Petra
Published: January 2009

Zusammenfassung: Erste Studien konnten zeigen, dass die Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung (ADHS) nicht nur mit einer ungünstigen Entwicklung des erkrankten Kindes verbunden ist, sondern auch Auswirkungen auf die psychosoziale Situation der Bezugspersonen hat. Die vorliegende Untersuchung ging der Frage nach, ob sich die Lebensqualität der Kinder mit ADHS sowie deren Bezugspersonen von der Lebensqualität nach Alter, Intelligenz und Schulform parallelisierter gesunder Kinder und deren Bezugspersonen in Abhängigkeit vom Alter (8-9 vs. 10-11 Jahre) unterscheidet. Weiterhin wurde das Erziehungsverhalten der Bezugspersonen untersucht. Insgesamt beurteilten 58 Mütter die Lebensqualität ihrer Kinder. Ferner schätzten sie ihre eigene Lebensqualität und ihr Erziehungsverhalten ein. Es ergaben sich keine Alterseffekte. Die durch die Mütter eingeschätzte Lebensqualität der Kinder mit ADHS war geringer gegenüber gesunden Kindern. Ebenso war das psychische und körperliche Wohlbefinden der Mütter mit einem an ADHS erkrankten Kind gegenüber den Müttern gesunder Kinder beeinträchtigt. Schließlich ergab sich ein negativeres Erziehungsverhalten der Mütter von Kindern mit ADHS gegenüber den Müttern gesunder Kinder. Die Befunde unterstreichen die Notwendigkeit familienorientierter Interventionsmaßnahmen bei der Behandlung von ADHS, die auch die psychosoziale Anpassung der Bezugspersonen berücksichtigt.
A study of lightning flashes attending periods of banded snowfall
Authors: Market Patrick S. , Becker Amy E.
Published: January 2009

Lightning flashes (N = 1088) associated with 24 thundersnow events in the central United States were analyzed to document flash polarity, signal strength, and multiplicity. Negative lightning flashes (N = 872; 80%) dominated positive flashes (N = 216; 20%) with wintry precipitation in this study, which stands in contrast to the majority of the research done on winter thunderstorms (primarily in Japan). Otherwise, limited work has been done, although thundersnow has been documented in the mid‐latitudes of North America, Europe and Asia. Statistics on peak amplitude were determined for negative (positive) flashes, yielding mean and standard deviation values of −24 kA ± 22 kA (+38 kA ± 34 kA). A subset of winter lightning events (N = 16) were then sought that occurred with banded (single or multiple) snowfall, as banding often denotes greater organization in the atmosphere (e.g., a jet streak aloft to aid in ascent, or a low level jet streak to aid with moisture and thermal transport) and thus the potential for deeper snow totals. Radar reflectivity values were recorded at the location of each lightning flash, as well as the maximum radar reflectivity within the associated snow band. The location of the lightning activity within the snow band was also noted as being either leading edge (LE), trailing edge (TE), core (C), or not correlated (NC), with respect to the motion of the parent band. The majority of lightning flashes were found downstream of areas of highest radar reflectivity with respect to the motion of the snow bands, and not with the highest reflectivity values. If one uses the highest reflectivity values in a snowband as a proxy for the greatest surface snowfall intensity, then the ground terminus of a cloud‐to‐ground lightning (CG) flash is often not co‐located with the heaviest snowfall rates. However, the work completed here does place the location of the typical CG flash ∼15 km downstream of the snowband location, so one could use the occurrence of lightning as a nowcasting tool for impending snow intensification at the site of the CG flash.
Surface morphology of domes in the Marius Hills and Mons Rümker regions of the Moon from Earth‐based radar data
Authors: Campbell Bruce A. , Hawke B. R. , Campbell Donald B.
Published: January 2009

Clusters and coalesced complexes of domes represent a relatively rare landform within the extensive, low‐relief, lunar maria. While they are typically spectroscopically similar to mare basalts emplaced by high‐volume, low‐viscosity eruptions, the large‐scale morphology of the domes is more consistent with slower emplacement and/or more viscous magma. We use new Earth‐based radar data to study the decimeter‐ to meter‐scale rock abundance, at the surface and buried within the probing range of the radar signal, of domes in the Marius Hills and Mons Rümker regions. Domes of the Marius Hills are characterized by high circular polarization ratio (CPR) values at 12.6‐cm and 70‐cm wavelength, similar to the near‐rim ejecta deposits of young lunar craters like Tycho, areas of large ejecta fragments near the rim of Meteor Crater, and blocky lavas such as SP flow in Arizona. We infer that a very rugged flow surface morphology, associated with the original dome‐forming eruption rather than postemplacement modification, exists beneath at most a few meters of regolith. Magmas with greater silica content than sampled lunar basalts are unlikely, so the blocky structure of the dome‐forming lava must arise from some combination of compositional change, effusion rate, and/or cooling effects not typically observed in basaltic landforms on the Earth. Much of the 80‐km diameter Mons Rümker has low backscatter and CPR at 12.6‐cm wavelength relative to nearby mare terrain. At 70‐cm wavelength, the northern and most of the southern parts of the complex are radar dark, but there is a radar bright feature that extends from the central region eastward into Oceanus Procellarum. We conclude that much of Mons Rümker is mantled by rock‐poor, fine‐grained pyroclastic material; the radar bright feature in the 70‐cm map is detectable owing to some combination of greater roughness (like the Marius domes) and thinner mantling cover.
Transient Focal Ischemia Induces Extensive Temporal Changes in Rat Cerebral MicroRNAome
Authors: Dharap Ashuthosh , Bowen Kellie , Place Robert , Li Long-Cheng , Vemuganti Raghu
Published: January 2009

MicroRNAs (miRNAs) are ∼22 nucleotides long, noncoding RNAs that control cellular function by either degrading mRNAs or arresting their translation. To understand their functional significance in ischemic pathophysiology, we profiled miRNAs in adult rat brain as a function of reperfusion time after transient middle cerebral artery occlusion. Of the 238 miRNAs evaluated, 8 showed increased and 12 showed decreased expression at least at 4 out of 5 reperfusion time points studied between 3 h and 3 days compared with sham. Of those, 17 showed > 5 fold change. Bioinformatics analysis indicated a correlation between miRNAs altered to several mRNAs known to mediate inflammation, transcription, neuroprotection, receptors function, and ionic homeostasis. Antagomir-mediated prevention of mir-145 expression led to an increased protein expression of its downstream target superoxide dismutase-2 in the postischemic brain. In silico analysis showed sequence complementarity of eight miRNAs induced after focal ischemia to 877 promoters indicating the possibility of noncoding RNA-induced activation of gene expression. The mRNA expression of the RNases Drosha and Dicer, cofactor Pasha, and the pre-miRNA transporter exportin-5, which modulate miRNA biogenesis, were not altered after transient middle cerebral artery occlusion. Thus, the present studies indicate a critical role of miRNAs in controlling mRNA transcription and translation in the postischemic brain.
Inferring Cerebrovascular Changes from Latencies of Systemic and Intracranial Pulses: A Model-Based Latency Subtraction Algorithm
Authors: Hu Xiao , Subudhi Andrew W , Xu Peng , Asgari Shadnaz , Roach Robert C , Bergsneider Marvin
Published: January 2009

Changes in cerebral blood flow velocity (CBFV) pulse latency reflect pathophysiological changes of the cerebral vasculature based on the theory of pulse wave propagation. Timing CBFV pulse onset relative to electrocardiogram QRS is practical. However, it introduces confounding factors of extracranial origins for characterizing the cerebral vasculature. This study introduces an approach to reducing confounding influences on CBFV latency. This correction approach is based on modeling the relationship between CBFV latency and systemic arterial blood pressure (ABP) pulse latency. It is tested using an existing data set of CBFV and ABP from 14 normal subjects undergoing pressure cuff tests under both normoxic and acute hypoxic states. The results show that the proposed CBFV latency correction approach produces a more accurate measure of cerebral vascular changes, with an improved positive correlation between beat-to-beat CBFV and the CBFV latency time series, for example, correlation coefficient increased from 0.643 to 0.836 for group-averaged cuff deflation traces at normoxia. In conclusion, this study suggests that subtraction of systemic ABP latency improves CBFV latency measurements, which in turn improve the characterization of cerebral vascular changes.
Dynamic MRI Using Iron Oxide Nanoparticles to Assess Early Vascular Effects of Antiangiogenic versus Corticosteroid Treatment in a Glioma Model
Authors: Varallyay Csanad G , Muldoon Leslie L , Gahramanov Seymur , Wu Yingjen J , Goodman James A , Li Xin , Pike Martin M , Neuwelt Edward A
Published: January 2009

The vascular effects of antiangiogenic treatment may pose problems for evaluating brain tumor response based on contrast-enhanced magnetic resonance imaging (MRI). We used serial dynamic contrast-enhanced MRI at 12 T to assess vascular responses to antiangiogenic versus steroid therapy. Athymic rats with intracerebral U87MG human glioma ( n = 17) underwent susceptibility-weighted perfusion MRI with ferumoxytol, a solely intravascular ultrasmall superparamagnetic iron oxide (USPIO) nanoparticle, followed by T1-weighted dynamic gadodiamide-enhanced MRI to measure vascular permeability. Rats were imaged before and after 24, 48, and 72 h of treatment with the antiangiogenic agent bevacizumab or the corticosteroid dexamethasone. Contrast agent extravasation was seen rapidly after gadodiamide, but not with ferumoxytol administration. Bevacizumab significantly decreased the blood volume and decreased permeability in tumors as determined by increased time-to-peak enhancement. A single dose of 45 mg/kg bevacizumab resulted in changes analogous to dexamethasone given in an extremely high dose (12 mg/kg per day), and was significantly more effective than dexamethasone at 2 mg/kg per day. We conclude that dynamic perfusion MRI measurements with ferumoxytol USPIO to assess cerebral blood volume, along with dynamic gadodiamide-enhanced MR to assess vascular permeability, hold promise in more accurately detecting therapeutic responses to antiangiogenic therapy.
Induction of Parkinson Disease-Related Proteins in Motor Neurons after Transient Spinal Cord Ischemia in Rabbits
Authors: Sakurai Masahiro , Kawamura Takae , Nishimura Hidekazu , Suzuki Hiroyoshi , Tezuka Fumiaki , Abe Koji
Published: January 2009

The mechanism of spinal cord injury has been thought to be related to the vulnerability of spinal motor neuron cells against ischemia. However, the mechanisms of such vulnerability are not fully understood. We investigated a possible mechanism of neuronal death by immunohistochemical analysis for DJ-1, PINK1, and α-Synuclein. We used a 15-min rabbit spinal cord ischemia model, with use of a balloon catheter. Western blot analysis for DJ-1, PINK1, and α-Synuclein; temporal profiles of DJ-1, PINK1, and α-Synuclein immunoreactivity; and double-label fluorescence immunocytochemical studies were performed. Western blot analysis revealed scarce immunoreactivity for DJ-1, PINK1, and α-Synuclein in the sham-operated spinal cords. However, they became apparent at 8 h after transient ischemia, which returned to the baseline level at 1 day. Double-label fluorescence immunocytochemical study revealed that both DJ-1 and PINK1, and DJ-1 and α-Synuclein were positive at 8 h of reperfusion in the same motor neurons, which eventually die. The induction of DJ-1 and PINK1 proteins in the motor neurons at the early stage of reperfusion may indicate oxidative stress, and the induction of α-Synuclein may be implicated in the programmed cell death change after transient spinal cord ischemia.
Small-molecule inhibitors of integrin α
2
β
1
that prevent pathological thrombus formation via an allosteric mechanism
Authors: Miller Meredith W. , Basra Sandeep , Kulp Daniel W. , Billings Paul C. , Choi Sungwook , Beavers Mary Pat , McCarty Owen J. T. , Zou Zhiying , Kahn Mark L. , Bennett Joel S. , DeGrado William F.
Published: January 2009

There is a grave need for safer antiplatelet therapeutics to prevent heart attack and stroke. Agents targeting the interaction of platelets with the diseased vessel wall could impact vascular disease with minimal effects on normal hemostasis. We targeted integrin α
2
β
1
, a collagen receptor, because its overexpression is associated with pathological clot formation whereas its absence does not cause severe bleeding. Structure–activity studies led to highly potent and selective small-molecule inhibitors. Responses of integrin α
2
β
1
mutants to these compounds are consistent with a computational model of their mode of inhibition and shed light on the activation mechanism of I-domain-containing integrins. A potent compound was proven efficacious in an animal model of arterial thrombosis, which demonstrates in vivo efficacy for inhibition of this platelet receptor. These results suggest that targeting integrin α
2
β
1
could be a potentially safe, effective approach to long-term therapy for cardiovascular disease.
Induction of labor versus expectant management for post‐date pregnancy: Is there sufficient evidence for a change in clinical practice?
Authors: WENNERHOLM ULLA‐BRITT , HAGBERG HENRIK , BRORSSON BENGT , BERGH CHRISTINA
Published: January 2009

Objectives. To compare perinatal and maternal outcomes between elective induction of labor versus expectant management of pregnancies at 41 weeks and beyond. Design. Systematic review and meta‐analysis. Methods. We searched PubMed, CINAHL, Cochrane Database of Systematic Reviews (CDSR), Database of Abstracts of Reviews of Effectiveness (DARE) and PsycINFO (1980 to November, 2007). Inclusion criteria were systematic reviews and randomized controlled trials comparing elective induction of labor versus expectant management of pregnancies at 41 weeks and beyond. Three or more reviewers independently read and evaluated all selected studies. Data were extracted and analyzed using Review Manager Software. Main outcome measures. Perinatal mortality. Results. Thirteen trials fulfilled the inclusion criteria for the meta‐analysis. Elective induction of labor was not associated with lower risk of perinatal mortality compared to expectant management (relative risks (RR): 0.33; 95% confidence intervals (CI): 0.10–1.09). Elective induction was associated with a significantly lower rate of meconium aspiration syndrome (RR: 0.43; 95% CI: 0.23–0.79). More women randomized to expectant management were delivered by cesarean section (RR: 0.87; 95% CI: 0.80–0.96). Conclusions. The meta‐analysis illustrated a problem with rare outcomes such as perinatal mortality. No individual study with adequate sample size has been published, nor would a meta‐analysis based on the current literature be sufficient. The optimal management of pregnancies at 41 weeks and beyond is thus unknown.
Early signs of maternal iron deficiency do not influence the iron status of the newborn, but are associated with higher infant birthweight
Authors: ERVASTI MARI , SANKILAMPI ULLA , HEINONEN SEPPO , PUNNONEN KARI
Published: January 2009

Objective. To investigate the associations between maternal iron status, pregnancy outcome and newborn iron status using sensitive and specific red blood cell indices reflecting iron‐deficient erythropoiesis. Design and setting. Cross‐sectional study in Kuopio University Hospital, Finland. Population. One hundred and ninety‐two pregnant women and their full‐term newborns (cord blood). Methods. Quartile analysis and Spearman correlations were used to investigate the associations of the iron status of pregnant women with that of their newborns, and with pregnancy outcome. Main outcome measures. Maternal and cord blood analysis including indices reflecting the hemoglobin (Hb) content of red blood cells as well as serum iron, transferrin saturation, transferrin receptor and ferritin. Gestational age, birthweight and placental weight. Results. The highest quartile of the maternal percentage of hypochromic red blood cells (%HYPOm) indicating the lowest iron status was associated with a high birthweight and a long duration of pregnancy. The newborns in this group did not show any signs of iron deficiency even though the maternal %HYPOm was elevated. Conclusions. In a well‐nourished maternal population, lower maternal iron status did not affect the iron accumulation on the fetal side. However, longer duration of pregnancy and growth of the fetus appeared to be associated with a lower amount of iron for Hb synthesis in maternal red blood cells, as reflected by the increased maternal %HYPOm, birthweight and length of gestation.
Red blood cell n‐3 polyunsaturated fatty acids in first trimester of pregnancy are inversely associated with placental weight
Authors: MAGNUSARDOTTIR ANNA R. , STEINGRIMSDOTTIR LAUFEY , THORGEIRSDOTTIR HOLMFRIDUR , HAUKSSON ARNAR , SKULADOTTIR GUDRUN V.
Published: January 2009

Objective. To investigate pregnancy outcome in relation to red blood cell (RBC) level of long‐chain n‐3 polyunsaturated fatty acids (PUFA) in the first trimester of pregnancy and the influence of lifestyle factors on the RBC level of long‐chain n‐3 PUFA. Design and setting. Observational study in a community with traditional fish and cod liver oil consumption. Population. Seventy‐seven healthy pregnant women. Methods. The PUFA composition of RBC was measured in the 11th to 15th week of pregnancy. The women answered food frequency and lifestyle questionnaires. Information on pregnancy outcome was collected from birth records. Main outcome measures. Placental weight, long‐chain n‐3 PUFA in diet and RBC, smoking. Results. Of all the pregnancy outcome variables tested, placental weight was the only one associated with long‐chain n‐3 PUFA in RBC. Inverse association was found between the proportion of long‐chain n‐3 PUFA in RBC and placental weight, adjusted for birthweight (p = 0.035). The proportion of long‐chain n‐3 PUFA in RBC was positively related to long‐chain n‐3 PUFA intake (p<0.001) and negatively related to smoking (p = 0.011). Conclusion. The human fetus relies on maternal supply and placental delivery of long‐chain n‐3 PUFA for optimal development and function, particularly of the central nervous system. Given the importance of dietary n‐3 PUFA during pregnancy, further studies are warranted to investigate the relationship between placental weight, maternal long‐chain n‐3 PUFA status and smoking.