bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrolysis of Maltoheptaose in Flow through Silicon Wafer Microreactors Containing Immobilised α‐Amylase and Glycoamylase
Authors: Melander Claes , Tüting Wiebke , Bengtsson Martin , Laurell Thomas , Mischnick Petra , Gorton Lo
Published: May 2006

In this study a silicon micro immobilised enzyme reactor (μIMER) has been applied for hydrolysis of maltoheptaose as a model maltodextrin and starch using immobilised μ‐amylase (from Aspergillus oryzae) and glycoamylase (from Aspergillus niger). The influence of several parameters was investigated such as immobilisation chemistry, buffer constituents, pH, temperature, flow rate and substrate concentration. The conversion efficiency profile of the substrate was measured and the long‐term stability of the reactor was tested. For separation and detection of the formed hydrolysis products, high‐performance anion‐exchange chromatography with pulsed amperometric detection (HPAEC‐PAD) was used. The results show that the μIMERs can also be used for hydrolysis of starch and also additionally be connected directly on‐line with, e.g., liquid chromatography, making it possible to perform on‐line characterisation and analysis of starch hydrolysis products.
A new strategy for prenatal diagnosis of homozygous α0‐thalassemia
Authors: Leung K. Y. , Liao C. , Li Q. M. , Ma S. Y. , Tang M. H. Y. , Lee C. P. , Chan V. , Lam Y. H.
Published: May 2006

Objectives

We have shown previously that ultrasound examination performed by one experienced operator can be useful to exclude homozygous α0‐thalassemia in a tertiary referral center. This study aimed to determine whether the technique was still applicable when performed by several operators and in different centers.

Methods

At the Maternal and Neonatal Hospital of Guangzhou (MNH) and Tsan Yuk Hospital of Hong Kong (TYH), women at risk of homozygous α0‐thalassemia were given the option of a non‐invasive approach (using serial ultrasound examinations at 12–15, 16–20 and 25–30 weeks' gestation) to exclude an affected pregnancy. The fetal cardiothoracic ratio (CTR) was measured at each of these examinations and the placental thickness was measured at 12–15 weeks' gestation. The operators of MNH received training on the ultrasound examination techniques at TYH and the quality of the subsequent ultrasound examinations was checked regularly. The final diagnosis of homozygous α0‐thalassemia was confirmed using an invasive test.

Results

Of 832 at‐risk pregnancies studied in the two hospitals, 168 (20.2%) were affected. The overall sensitivity and specificity of the non‐invasive approach was 100% and 95.6%, respectively. At MNH, the need for an invasive test was reduced by 80.8%, and all the affected pregnancies were diagnosed before 24 weeks' gestation. The results achieved at MNH were comparable with those at TYH. The at‐risk pregnancies including the affected ones presented at a more advanced gestational age at MNH. At each hospital, one affected pregnancy was missed at the 12‐week scan but this was subsequently detected at the 15–18‐week scan.

Conclusions

This non‐invasive approach to exclude homozygous α0‐thalassemia can be applicable when it is performed by several operators and in different centers. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Mechanochemical copolymerization of poly(vinyl chloride) with methyl methylacrylate in an open mill machine
Authors: He Peixin , He Benqiao , Xiao Weidong , Zhang Yuhong
Published: May 2006

Mechanical degradation of poly(vinyl chloride) (PVC) and mechanochemical copolymerization in poly(vinyl chloride)/methyl methylacrylate (PVC/MMA) systems were studied in an open mill machine. The effects of the mastication temperature, mastication time, and additives (oxygen, THF, or hydroquinone) on the mechanical degradation of PVC were investigated. The molecular weight of PVC decreased with increasing mastication time, and the efficiency of the mechanodegradation of PVC was lowered with increasing mastication temperature. The effects of the ratio of PVC to MMA, thin‐passage time, and initiator on mechanochemical copolymerization also were studied. The experimental results indicated that the degree of copolymerization increased with increasing thin‐passage times up to 45 times and then remained constant. There was a maximum degree of copolymerization at a ratio of 0.22 g/mL (PVC/MMA), and the efficiency of copolymerization always decreased with increasing time. The maximum degree and efficiency of copolymerization were 5.8 and 89%, respectively. The poly(vinyl chloride‐co‐methyl methylacrylate) copolymer can further improve the interfacial adhesion of PVC and PMMA. Thus it improves the mechanical properties of the PVC/CPE blend more effectively than pure PMMA. J. VINYL. ADDIT. TECHNOL. 12:42–48, 2006. © 2006 Society of Plastics Engineers.
Performance of tocopherols as antioxidants in ABS
Authors: Suffield Rachel M. , Dillman Steven H. , Haworth James E.
Published: May 2006

Mixed tocopherols, γ‐tocopherol, and δ‐tocopherol were evaluated for antioxidant performance in acrylonitrile–butadiene–styrene by using oxidative induction time as the response. Three commonly used phenolic antioxidants and vitamin E (α‐tocopherol) were used as controls. Mixed tocopherols were found to have a greater antioxidant effect than the hindered phenolic antioxidants or vitamin E in acrylonitrile–butadiene–styrene. γ‐tocopherol was found to be primarily responsible for the improved performance of mixed tocopherols. J. VINYL. ADDIT. TECHNOL. 12:66–72, 2006. © 2006 Society of Plastics Engineers
Antioxidant performance of mixed tocopherols in styrenic block copolymers
Authors: Suffield Rachel M. , Kiesser Jordan E. , Dillman Steven H.
Published: May 2006

Mixed tocopherols (MT) containing a predominance of γ‐tocopherol were evaluated for antioxidant (AO) performance in polybutadiene‐ and polyisoprene‐based styrenic block copolymers (SBS and SIS, respectively) by using oxidative induction time as a measure of AO performance. A conventional hindered phenolic AO and α‐tocopherol (vitamin E) were evaluated in comparison. MT exhibited significantly higher performance than the controls in both SIS and SBS polymers. J. VINYL ADDIT. TECHNOL., 12:73–77, 2006. © 2006 Society of Plastics Engineers
On‐demand public‐key management for mobile ad hoc networks
Authors: Li Ruidong , Li Jie , Liu Peng , Chen Hsiao‐Hwa
Published: May 2006

A mobile ad hoc network (MANET) is the cooperative engagement of a collection of wireless mobile nodes without the aid of any established infrastructure or centralized administration. The conventional security solutions to provide key management through accessing trusted authorities or centralized servers are infeasible for this new environment since mobile ad hoc networks are characterized by the absence of any infrastructure, frequent mobility, and wireless links. In this paper, we propose an on‐demand, fully localized, and hop‐by‐hop public key management scheme for MANETs. It can be performed by generating public/private key pairs by nodes themselves, issuing certificates to neighboring nodes, holding these certificates in their certificate repositories, and providing authentication service adaptive quickly to the dynamic topology of the network without relying on any servers. Also, our scheme can be performed successfully as long as there is a physical communication line between two nodes, and it is accustomed well to the on‐demand routing for MANETs. Copyright © 2006 John Wiley & Sons, Ltd.
A new approach for random key pre‐distribution in large‐scale wireless sensor networks
Authors: Ren Kui , Zeng Kai , Lou Wenjing
Published: May 2006

In a wireless sensor network (WSN), pre‐distribution of secret keys is possibly the most practical approach to protect network communications. To meet the stringent resource constraints of the sensor nodes, key pre‐distribution schemes should be highly efficient, require as little storage space as possible, and at the same time, maintain a strong security strength, that is, high resilience against node capture. In this paper, a new approach for random key pre‐distribution is proposed to achieve both efficiency and security goals. The novelty of this approach lies in that, instead of using a key pool consisting of random keys, a key generation technique is carefully designed such that a large number of random keys can be represented by a small number of key‐generation keys. Then, instead of storing a big number of random keys, each sensor node stores a small number of key‐generation keys while computing the shared secret keys during the bootstrapping phase on the fly using the computationally efficient hash function. The proposed scheme outperforms the previous random key pre‐distribution schemes in that it reduces the storage requirement significantly while holding the comparable security strength, as shown by our thorough analysis and simulation. Copyright © 2006 John Wiley & Sons, Ltd.
Cooperation enforcement schemes for MANETs: a survey
Authors: Marias G. F. , Georgiadis P. , Flitzanis D. , Mandalas K.
Published: May 2006

The employment of adequate trust methods in mobile ad hoc networks (MANET) has been receiving increasing attention during the last few years, and several trust and security establishment solutions that rely on cryptographic and hashing schemes have been proposed. These schemes, although effective, produce significant processing and communication overheads and consume energy, and, hence, they do not take into account the idiosyncrasies of a MANET. More recently, cooperation enforcement methods have been proposed for trust establishment in MANET. These schemes, classified as reputation‐based and credit‐based, are considered suitable for ad hoc networks, where key or certificate distribution centers are absent or ephemerally present, and for networks that consist of devices with limited processing, battery, and memory resources. Cooperation enforcement methods do not provide strong authentication of entities. Instead, they contribute to the identification of the trustworthiness of peers and to the enforcement cooperation using mutual incentives. This paper surveys the most important cooperation enforcement methods that have been introduced, providing a comprehensive comparison between the different proposed schemes. Copyright © 2006 John Wiley & Sons, Ltd.
A location‐based naming mechanism for securing sensor networks
Authors: Zhou Yun , Fang Yuguang
Published: May 2006

Conventional sensor networks name every node with an identifier from a one dimension name space that has no meaning but identification function. However, it is much useful to let every node identifier carry more characteristics of the node itself. This paper introduces the naming problem for sensor networks in the literature for the first time, and proposes a location‐based naming mechanism (LBN) for sensor networks, in which location information is embedded into node identifier and acts as an inherent node characteristic to provide authentication service in local access control. When LBN is enforced, the impacts of many attacks to sensor network topology can be limited in a small area. A link layer authentication (LLA) scheme is also proposed to further decrease the impacts of those attacks. Our LBN and LLA can be combined and act as an efficient solution against a wide range of attacks in sensor networks. Copyright © 2006 John Wiley & Sons, Ltd.
Mass spectrometry‐based profiling of phospholipids and sphingolipids in extracts from Saccharomyces cerevisiae
Authors: Guan Xue Li , Wenk Markus R.
Published: May 2006

Lipids are rapidly moving to centre stage in many fields of biological sciences. Lipidomics, the systems‐level scale analysis of lipids and their interacting factors, is thus an emerging field which holds great promise for drug and biomarker discovery. Here we present a mass spectrometry‐based approach for profiling of polar lipids, in particular phospholipids and sphingolipids, in Saccharomyces cerevisiae. The first step includes semi‐quantitative surveys of lipids in an untargeted fashion, which is particularly powerful for detection of changes that cannot easily be anticipated. This leads to the identification of ions with increased or decreased signal intensities. Comprehensive theoretical calculation of the masses of yeast phospholipid and sphingolipid molecular species, based on fatty acyl and headgroup heterogeneity, is next used to tentatively assign ions of interest. Subsequent targeted analysis using tandem mass spectrometry allows for characterization and quantification of phospholipids and sphingolipids. Given the high degree of conservation in pathways of lipid metabolism between different organisms, it can be expected that this method will lead to the discovery of novel enzymatic activities and modulators of known ones, particularly when used in combination with genetic and chemogenetic libraries and screens. We validated the method using the EUROSCARF library of non‐essential deletion mutants. Mutants of SCS7, a lipid hydroxylase, and SLC1, a putative acyl transferase with unknown substrate specificity, were profiled for their phospholipid and sphingolipid content. The observed changes in lipid profiles are consistent with previous observations and extend our knowledge on in vivo substrate use under permissive growth conditions. Copyright © 2006 John Wiley & Sons, Ltd.
Chrono‐ethologic investigations on the Queensland koala (Phascolarctos cinereus adustus) in captivity
Authors: Richter Cora
Published: May 2006

The chronologic behavior pattern of a separately kept pair of koalas at the Tiergarten Schönbrunn (Vienna Zoo) was investigated with regard to how the patterns are distributed over 24 hr and the “zeitgeber” (from German; synonym “entraining agent”) on which they depend. The data was collected continuously by means of infrared video recording over 3 months, January–March 2003 (2,160 hr/animal). Observations were made using the scan‐sampling method at 1‐min intervals. The total activity and each single behavior are described and analyzed in chrono‐ethograms and activity profiles for the first time in this species. The main activity of both koalas occurs between 1:00 AM and 4:00 AM, a continuous sleeping period occurs between 11:00 AM and 3:00 PM (sometimes until 4:00 PM). They become active 1 hr before darkness and inactive 1 hr before dawn (anticipation). During the day koalas are only awakened and become active due to care measures (feedings/weighing). “Zeitgeber” influencing the koalas' behavior are feeding and weighing as well as the light/dark change. To influence the koalas' endogenous rhythm as little as possible, the keepers' daily routine (time and frequency) has to be modified. Zoo Biol 0:1–12, 2006. © 2006 Wiley‐Liss, Inc.
Assessing personality traits associated with depression: the utility of a tiered model
Authors: PARKER GORDON , MANICAVASAGAR VIJAYA , CRAWFORD JO , TULLY LUCY , GLADSTONE GEMMA
Published: May 2006

Background. We sought to develop a refined measure of eight personality traits or constructs observed in those who develop depression. We report the psychometric properties of the derived Temperament and Personality (T&P) questionnaire, as well as a pilot study examining its capacity to differentiate over-represented personality traits in those with depression.

Method. The factor structure of the T&P measure was examined in a general practice sample of 529 subjects. We imposed a range of factorial solutions to determine how higher-order molar constructs arborized to eight lower-order constructs. Scale scores generated at each derived tier were contrasted for 52 out-patients with major depression and control subjects from the general practice sample to pursue over-represented personality constructs, and to clarify if an optimal number of constructs could be identified.

Results. In the factor analysis, some 90% of the items loaded on their a priori construct. The questionnaire showed high internal consistency, test–retest reliability and minimal sensitivity to mood state effects. Analyses rejected the hypothesis that risk to depression might be generally affected by individuals merely scoring high on all ‘normal’ personality styles, whether higher-order or lower-order traits.

Conclusions. Findings suggest that, while identified constructs linked well with the widely accepted theoretical model of personality (the Five Factor Model) at one tier, such a fixed model may be too inflexible. We therefore detail potential advantages to using a multi-tiered model of personality traits in application studies.
Abnormal function of the brain system supporting motivated attention in medicated patients with schizophrenia: an fMRI study
Authors: LIDDLE PETER F. , LAURENS KRISTIN R. , KIEHL KENT A. , NGAN ELTON T. C.
Published: May 2006

Background. Patients with schizophrenia have an impaired ability to generate activity that is appropriate to current circumstances and goals.

Method. We report a study using functional magnetic resonance imaging (fMRI) to examine cerebral activity during a three-tone auditory oddball target detection task in a sample of 28 patients with schizophrenia and 28 healthy controls.

Results. The patients exhibited significantly less activation in response to target stimuli relative to baseline in an extensive set of sites in association neocortex, paralimbic cortex, limbic structures and subcortical nuclei, yet demonstrated a normal level of activation in the sensorimotor cortex. Comparison of activity elicited by rare target stimuli with that elicited by equally rare novel stimuli makes it possible to distinguish cerebral activity associated with attention to behaviourally salient stimuli from activity associated with attending to other attention-capturing stimuli. This comparison revealed that the patients with schizophrenia also exhibited a deficit in activation of basal forebrain areas that mediate motivation during the processing of behaviourally salient stimuli, including the amygdala, ventral striatum, orbital frontal cortex and rostral anterior cingulate cortex.

Conclusion. Patients with schizophrenia have a deficit in function of the brain system concerned with mediating motivation, in addition to a more general deficit in the cerebral response to attention-captivating stimuli.
Brain reserve and cognitive decline: a non-parametric systematic review
Authors: VALENZUELA MICHAEL J. , SACHDEV PERMINDER
Published: May 2006

Background. A previous companion paper to this report (Valenzuela & Sachdev, Psychological Medicine 2006, 36, 441–454) suggests a link between behavioural brain reserve and incident dementia; however, the issues of covariate control and ascertainment bias were not directly addressed. Our aim was to quantitatively review an independent set of longitudinal studies of cognitive change in order to clarify these factors.

Method. Cohort studies of the effects of education, occupation, and mental activities on cognitive decline were of interest. Abstracts were identified in MEDLINE (1966–September 2004), CURRENT CONTENTS (to September 2004), PsychINFO (1984–September 2004), Cochrane Library Databases and reference lists from relevant articles. Eighteen studies met inclusion criteria. Key information was extracted by both reviewers onto a standard template with a high level of agreement. Cognitive decline studies were integrated using a non-parametric method after converting outcome data onto a common effect size metric.

Results. Higher behavioural brain reserve was related to decreased longitudinal cognitive decline after control for covariates in source studies (ϕ=1·70, p<0·001). This effect was robust to correction for both multiple predictors and multiple outcome measures and was the result of integrating data derived from more than 47000 individuals.

Conclusions. This study affirms that the link between behavioural brain reserve and incident dementia is most likely due to fundamentally different cognitive trajectories rather than confound factors.
Learners and users of English in China
Authors: Yang Jian
Published: May 2006

Just how many millions are there? China’s huge English-knowing population of 200–350 million is often cited as evidence of the language being nativized in the world’s most populous country. We may note, however, that the words user and learner are used interchangeably in reference to its speakers of English. When however the focus is on the nativization of English in China, a country in Kachru’s ‘Expanding Circle’ of Englishes, it is imperative to distinguish between users and learners of the language. Kachru points out that institutionalized varieties of English in Outer Circle countries have four functions: the instrumental, the regulative, the interpersonal, and the imaginative/innovative. For English to perform any such functions, there needs to be a large number of proficient bilingual users of the language – which seems not to be the case in China, where English is primarily learned in the classroom as a foreign language. This means that college graduates should have learned the most English, but some constraining factors have prevented the majority of them from obtaining an advanced level of proficiency.
World Englishes and contrastive rhetoric
Authors: Yajun Jiang , Zhou Chenggang
Published: May 2006

WE ARGUE here that a ‘paradigm gap’ has prevented recent research into world Englishes (WEs) and contrastive rhetoric (CR) from being mutually useful, and suggest particular areas in which insights from CR may benefit in particular the study of WEs. English in its standard ‘native’ form(s) is fast becoming the world’s lingua franca of science, commerce, the mass media, and entertainment. As a result, its non-native uses and users have become significant in at least the following eleven fields: applied linguistics, sociolinguistics, critical linguistics, contrastive rhetoric, second language acquisition, traditional English studies, lexicography, mass communication studies, cultural studies, pragmatics, and text linguistics (cf. Bolton, 2003a). We hope that the present study will contribute to the debate.
Medical rhetoric: A contrastive study of Arabic and English in the UAE
Authors: Khuwaileh Abdullah
Published: May 2006

THE AIM of this paper is to study the rhetorical use of tense and voice in research writing undertaken in both English and Arabic medical research. Six reports (three by native speakers of English, three by native speakers of Arabic) were analysed, all being typical of texts containing functional information. Moreover, several medical prescriptions were also analysed. The analysis showed important differences between medical English and medical Arabic, in terms of tense, voice and the use of modals. The study concludes with a number of practical and research recommendations.
In Memoriam: Maninging Miclat
Authors: Shao X. Z.
Published: May 2006

Poem in memoriam: Maningning Miclat : an established Pilipino woman painter and poet, born in Beijing in 1972, committed suicide in Manila in 2000.
Surveillance of Salmonella spp. and Campylobacter spp. in poultry production flocks in The Netherlands
Authors: van de GIESSEN A. W. , BOUWKNEGT M. , DAM-DEISZ W. D. C. , van PELT W. , WANNET W. J. B. , VISSER G.
Published: May 2006

In The Netherlands, a national programme for the surveillance of zoonotic bacteria in farm animals has been operative since 1997. We describe the results of the surveillance of Salmonella spp. in flocks of laying hens and broilers and of Campylobacter spp. in broiler flocks in the period 1999–2002. The prevalence of Salmonella spp. in laying-hen flocks has significantly decreased from 21·1% in 1999 to 13·4% in 2002. This decreasing trend might indicate that the control measures taken by the poultry industry were effective. S. Enteritidis was the predominant serovar in laying hens accounting for one third of the positive flocks. Although prevalence estimates for Salmonella spp. in broiler flocks did not yield a significant decreasing trend in 1999–2002, a decrease in Salmonella prevalence to 11% was measured in 2002. During the study period, S. Paratyphi B var. Java emerged in broilers to become the predominant serovar in 2002 accounting for one third of the positive flocks. The prevalence of Campylobacter spp. in broiler flocks did not increase nor decrease continuously between 1999 and 2002, which roughly corresponds with the monitoring results from the poultry industry. In this period, the estimated flock prevalence roughly averaged around 20%, with C. jejuni being the predominant species. The approach of monitoring presented in this paper can serve as a blueprint for monitoring schemes in farm animal populations to be developed in the context of the EC Zoonoses Directive.
High case-fatality rates of meningococcal disease in Western Norway caused by serogroup C strains belonging to both sequence type (ST)-32 and ST-11 complexes, 1985–2002
Authors: SMITH I. , CAUGANT D. A. , HØIBY E. A. , WENTZEL-LARSEN T. , HALSTENSEN A.
Published: May 2006

A total of 293 meningococcal disease (McD) patients from Western Norway hospitalized during 1985–2002 were examined for risk factors related to death. The case-fatality rate (CFR) increased from 4% during 1985–1993 to 17% during 1994–2002. We analysed the phenotypic and genotypic characteristics of the meningococcal patient isolates, with the aim of identifying whether highly virulent meningococcal strains contributed to the increased CFR. The Norwegian epidemic strain B:15:P1.7,16/ST-32 complex was overall the most common phenotype/genotype (n=75) and caused most deaths (n=9; CFR 12·0%). However, fatality was significantly associated with disease caused by serogroup C meningococcal strains; C:15:P1.7,16/ST-32 and C:2a/ST-11 complex strains, which had the highest CFRs of 21·1% and 18·2% respectively. Serogroup B strains of the ST-32 complex differing by serotype and/or serosubtype from the epidemic strain had a CFR of 5·1%, while the CFR of disease caused by other strains (all phenotypes and genotypes pooled) was 2·2%. The distribution of phenotypes/clonal complexes varied significantly between 1985–1993 and 1994–2002 (P<0·001); B:15/ST-32 complex strains decreased whereas both C:15:P1.7,16/ST-32 complex strains and strains with other phenotypes/clonal complexes increased. Our results indicate that C:15:P1.7,16/ST-32 and C:2a/ST-11 complex strains were highly virulent strains and contributed to the high CFR of McD in patients from Western Norway. To reduce fatality, rapid identification of such virulent strains is necessary. In addition, early and specific measures should include public information, vaccination of populations at risk of disease and carriage eradication, when clustering of patients occurs.
Interpersonal Fears among Patients with Panic Disorder with Agoraphobia
Authors: Hoffart Asle , Hackmann Ann , Sexton Harold
Published: May 2006

To study the role of catastrophic interpersonal cognitions in panic disorder with or without agoraphobia, a questionnaire listing such items – the Interpersonal Panic Fear Questionnaire (IPFQ) – was constructed and administered to English and Norwegian samples. The results of the factor analysis indicated a three-factor structure of interpersonal fears: fear of negative evaluation, fear of being trapped and separated from safe persons and places, and fear of being neglected. The corresponding three IPFQ scales had satisfactory internal consistency and sensitivity to change following therapeutic intervention, discriminated well between diagnostic groups, and correlated moderately with measures of other dimensions of panic disorder and agoraphobia. The construct validity of the interpersonal fears was further supported by mostly significant relationships between the IPFQ scales and a measure of agoraphobic avoidance, when the contribution of intrapersonal (physical, loss of control) fears was controlled.
Evaluation eines maltherapeutischen Angebots für onkologische Patienten in einem Akutkrankenhaus
Authors: Grulke Norbert , Bailer Harald , Stähle Stephanie , Kächele Horst
Published: May 2006

Zusammenfassung. Fragestellung: Wir pilotieren die Durchführbarkeit einer prospektiv angelegten maltherapeutischen Studie unter Einsatz psychometrischer Instrumente und unter den Routinebedingungen der hämatologisch-onkologischen Stationen eines universitären Akutkrankenhauses. Methode: Es werden 21 an einem bereits seit längerem bestehenden offenen maltherapeutischen Gruppenangebot teilnehmende Krebspatienten mit 24 Nichtteilnehmern auf den Dimensionen Lebensqualität (EORTC QLQ-30), Gestimmtheit (POMS), Angst und Depression (HADS) und Krankheitsbewältigung (MAC-Scales) verglichen. Die zweite Messung erfolgte drei Monate später. Ergebnisse: Die Ergebnisse deuten auf einen Vorteil für die Interventionsgruppe hin. Diskussion: Die Ergebnisse werden kritisch reflektiert und mögliche alternative Erklärungen werden diskutiert. Schlussfolgerung: Psychometrische Erhebungen scheinen den kreativtherapeutischen Prozess entgegen den Befürchtungen der beteiligten Kunsttherapeutinnen nicht zu stören. Maltherapie ist eine Intervention, die im akutklinischen Setting nur von wenigen Krebspatienten angenommen wird. Für diese Patienten stellt sie möglicherweise eine wirksame Unterstützung dar, allerdings sollten die vorläufigen Ergebnisse zurückhaltend interpretiert werden.
Tagtraumimagination und bildnerisches Gestalten mit verhaltensauffälligen Kindern und Jugendlichen an Schulen
Authors: Hampe Ruth
Published: May 2006

Zusammenfassung. Dargestellt wird eine Projektarbeit an drei Schultypen zur Integration präventiver Maßnahmen für verhaltensauffällige Schüler. Es geht um die Einbindung von Tagtraumimaginationen zur Stützung der Persönlichkeitsentwicklung. Anhand des Motives “Haus“ wird die Vermittlung von Tagträumen mit dem ästhetisch-gestalterischen Ausdruck anhand von Fallbeispielen dokumentiert.
Die “Lebenslinie“: Visualisierungstechnik für die therapeutische Praxis
Authors: Schwan Martin
Published: May 2006

Zusammenfassung. Die “Lebenslinie“ wird vorgestellt und über ihren kunsttherapeutischen Ursprungskontext für die allgemeine psychotherapeutische Praxis empfohlen. Der Artikel richtet sich schulenübergreifend an Psychotherapeuten in Praxis und Ausbildung. Basierend auf einer qualitativen Forschungsarbeit, die sich mit der Herstellung von Kohärenz und Kontinuität bei chronischen Schmerzpatienten befasste, werden Optimierungsmöglichkeiten eines dialektischen Zusammenspiels sprachlicher und zeichnerischer Lebenssymbolisation im Hinblick auf subjektiven Erkenntniszuwachs diskutiert. Exemplarisch werden zwei Lebenslinien unter gestalttheoretischer Perspektive vorgestellt. Eine optimale Anwendung soll durch ein theoretisches Modell erleichtert werden, das zwischen einer Verwendungsweise als Abbild oder Symbol einschließlich der praktischen Konsequenzen unterscheidet. Der Artikel schließt mit Erfahrungen im Umgang mit der “Lebenslinie“ aus der Praxis des Autors. Es werden konkrete Anwendungsmöglichkeiten im Rahmen einer Anamnese angeregt.
Vergleich zweier schulbasierter Programme zur Prävention depressiver Symptome bei Jugendlichen
Authors: Pössel Patrick , Horn Andrea B. , Hautzinger Martin
Published: May 2006

Zusammenfassung. Theoretischer Hintergrund: Depressive Störungen im Jugendalter sind ein weitverbreitetes Problem mit weitreichenden psychosozialen Folgen. Um beidem vorzubeugen wurde ein kognitiv-verhaltenstherapeutisches und ein auf dem Paradigma des Expressiven Schreibens beruhendes universales schulbasiertes Präventionsprogramm entwickelt. Fragestellung: Haben die beiden Präventionsprogramme positive Wirkung auf depressive Symptomatik und Lebenszufriedenheit Jugendlicher? Methode: Es wurde eine randomisierte Kontrollgruppenstudie mit 3-Monats Follow-up an 579 Realschülern und -schülerinnen der 8. Klasse durchgeführt. Ergebnisse: Das kognitiv-verhaltenstherapeutische Programm wirkt in Abhängigkeit der Ausgangssymptomatik kurz- bzw. mittelfristig auf die depressive Symptomatik, während das Schreibprogramm unabhängig von der Ausgangssymptomatik kurz- und mittelfristig positiv auf die Lebenszufriedenheit wirkt. Schlussfolgerungen: Trotz Einschränkungen in Bezug auf die Vergleichbarkeit beider Programme liefert die Studie erste wichtige Ergebnisse in Richtung eines Vergleichs unterschiedlicher Interventionen in der Präventionsforschung von Depressionen.
ProACT + E: Ein Programm zur Prävention von “bullying“ an Schulen und zur Förderung der positiven Entwicklung von Schülern
Authors: Spröber Nina , Schlottke Peter F. , Hautzinger Martin
Published: May 2006

Zusammenfassung. Theoretischer Hintergrund: Diese Studie untersucht die Wirksamkeit eines für weiterführende Schulen entwickelten universalen, primärpräventiven Mehr-Ebenen-Programms. Fragestellung: Es wurde angenommen, dass a) durch die Einführung des kognitiv-verhaltenstheoretisch orientierten Trainingsprogramms Bullying/Viktimisierung in Schulen wirkungsvoll reduziert und positives Sozialverhalten verbessert werden kann und b) das Verhalten der Schüler sich dann am nachhaltigsten in der gewünschten Richtung verändert, wenn die Eltern mit einem Elterntraining einbezogen werden. Methode: An der Studie nahmen 145 Schüler (5. Klassen; Realschule) teil. Die Evaluation des Programms erfolgte in Form eines Prä-/Posttestdesigns mit Kontrollgruppe (Nachuntersuchung nach 2 Wochen und 4 Monaten). Die Schulen wurden zufällig drei Bedingungen (proACT: Klassentraining, proACT + E: Klassen- und Elterntraining, Kontrollgruppe: unspezifische Intervention) zugewiesen. Ergebnisse: Die Ergebnisse auf der Basis der Selbsteinschätzungen der Schüler zeigen eine signifikante und stabile Reduktion problematischer Verhaltensweisen (verbale Aggression, Gewaltbereitschaft). Diese Verbesserung der sozialen Kompetenzen und Konfliktlösungsmöglichkeiten der Schüler gelingt nur unter Einbeziehung der Eltern. Schlussfolgerung: Die Befunde belegen die Akzeptanz, die Einsetzbarkeit und die Wirksamkeit eines schulbasierten Gewaltpräventionsprogramms. Die Nichtberücksichtigung der Eltern verhindert diese positiven Effekte.
Coarse-grained interaction potentials for anisotropic molecules
Authors: Babadi M. , Everaers R. , Ejtehadi M. R.
Published: May 2006

We have proposed an efficient parametrization method for a recent variant of the Gay Berne potential for dissimilar and biaxial particles [Phys. Rev. E 67, 041710 (2003)] and demonstrated it for a set of small organic molecules. Compared with the previously proposed coarse-grained models, the new potential exhibits a superior performance in close contact and large distant interactions. The repercussions of thermal vibrations and elasticity have been studied through a statistical method. The study justifies that the potential of mean force is representable with the same functional form, extending the application of this coarse-grained description to a broader range of molecules. Moreover, the advantage of employing coarse-grained models over truncated atomistic summations with large distance cutoffs has been briefly studied.
[ Pb ( H 2 O ) ] 2 + and [Pb(OH)]+: Four-component density functional theory calculations, correlated scalar relativistic constrained-space orbital variation energy decompositions, and topological analysis
Authors: Gourlaouen Christophe , Piquemal Jean-Philip , Parisel Olivier
Published: May 2006

Within the scope of studying the molecular implications of the Pb2+ cation in environmental and polluting processes, this paper reports Hartree-Fock and density functional theory (B3LYP) four-component relativistic calculations using an all-electron basis set applied to [Pb(H2O)]2+ and [Pb(OH)]+, two complexes expected to be found in the terrestrial atmosphere. It is shown that full-relativistic calculations validate the use of scalar relativistic approaches within the framework of density functional theory. [Pb(H2O)]2+ is found C2v at any level of calculations whereas [Pb(OH)]+ can be found bent or linear depending of the computational methodology used. When Cs is found the barrier to inversion through the C∞v structure is very low, and can be overcome at high enough temperature, making the molecule floppy. In order to get a better understanding of the bonding occurring between the Pb2+ cation and the H2O and OH− ligands, natural bond orbital and atoms-in-molecule calculations have been performed. These approaches are supplemented by a topological analysis of the electron localization function. Finally, the description of these complexes is refined using constrained-space orbital variation complexation energy decompositions.
Stereographic projection path-integral simulations of (HF)n clusters
Authors: Avilés Michael W. , Gray Philip T. , Curotto E.
Published: May 2006

We perform several quantum canonical ensemble simulations of (HF)n clusters. The HF stretches are rigid, and the stereographic projection path-integral method is employed for the simulation in the resulting curved configuration space. We make use of the reweighted random series techniques to accelerate the convergence of the path-integral simulation with respect to the number of path coefficients. We develop and test estimators for the total energy and heat capacity based on a finite difference approach for non-Euclidean spaces. The quantum effects at temperatures below 400K are substantial for all sizes. We observe interesting thermodynamic behaviors in the quantum simulations of the octamer and the heptamer.
A general and efficient pseudopotential Fourier filtering scheme for real space methods using mask functions
Authors: Tafipolsky Maxim , Schmid Rochus
Published: May 2006

A scheme for the Fourier filtering of pseudopotentials in real space calculations is proposed, in order to reduce the artifact of positional energy dependence (“egg box” effect). It is based on an improved version of the mask function method poposed by Wang [Phys. Rev. B 64, 201107–1 (2001)]. It is easy to implement, efficient, and accurate. By using atom-centered compensation charges, the local part of the pseudopotential becomes short ranged and can be filtered on the same footing as the nonlocal parts. A major advantage of the approach is that a generic set of parameters can be used for different pseudopotentials. A balanced parameter set is derived and validated. In this context a strategy to monitor the extent of grid dependence is introduced. It is found that, given a sufficiently fine grid spacing is used to represent the atomic valence density, the positional energy dependence can be reduced below 0.1mhartree for all investigated atoms. On the example of a D3h symmetric Si5 cluster and the C60 molecule it is demonstrated that the artificial symmetry breaking of both bond lengths and orbital energies can substantially be reduced by the filtering scheme.
Ultrafast electron diffraction: Excited state structures and chemistries of aromatic carbonyls
Authors: Park Sang Tae , Feenstra Jonathan S. , Zewail Ahmed H.
Published: May 2006

The photophysics and photochemistry of molecules with complex electronic structures, such as aromatic carbonyls, involve dark structures of radiationless processes. With ultrafast electron diffraction (UED) of isolated molecular beams it is possible to determine these transient structures, and in this contribution we examine the nature of structural dynamics in two systems, benzaldehyde and acetophenone. Both molecules are seen to undergo a bifurcation upon excitation (S2). Following femtosecond conversion to S1, the bifurcation leads to the formation of molecular dissociation products, benzene and carbon monoxide for benzaldehyde, and benzoyl and methyl radicals for acetophenone, as well as intersystem crossing to the triplet state in both cases. The structure of the triplet state was determined to be “quinoidlike” of ππ* character with the excitation being localized in the phenyl ring. For the chemical channels, the product structures were also determined. The difference in photochemistry between the two species is discussed with respect to the change in large amplitude motion caused by the added methyl group in acetophenone. This discussion is also expanded to compare these results with the prototypical aliphatic carbonyl compounds, acetaldehyde and acetone. From these studies of structural dynamics, experimental and theoretical, we provide a landscape picture for, and the structures involved in, the radiationless pathways which determine the fate of molecules following excitation. For completeness, the UED methodology and the theoretical framework for structure determination are described in this full account of an earlier communication [J. S. Feenstra et al., J. Chem. Phys. 123, 221104 (2005)].
Excluded volume effect on confined polymer translocation through a short nanochannel
Authors: Xie Yongjun , Yang Haiyang , Yu Hongtao , Shi Qinwei , Wang Xiaoping , Chen Jie
Published: May 2006

We simulated the translocation process of a polymer chain from a source container to a drain container through a short nanochannel. We utilized the bond fluctuation model coupled with Monte Carlo dynamics in our simulations. The calculation results show that the excluded volume effect significantly affects the polymer’s translocation time τ. This time depends nonmonotonically on the polymer length N. For a fixed nanochannel length, τ decreases when the polymer length increases. τ, however, increases when the polymer length exceeds a certain threshold. This observation differs from those predicated for a Gaussian chain. In this paper, we will further present our findings to explain this phenomenon. The knowledge we gain from this research can enhance the understanding of complex transport processes in many biological systems.
ITO
∕
Ti
∕
Au
Ohmic contacts on n-type ZnO
Authors: Kang B. S. , Chen J. J. , Ren F. , Li Y. , Kim H.-S. , Norton D. P. , Pearton S. J.
Published: May 2006

The specific contact resistivity and chemical intermixing of indium-tin-oxide (ITO)∕Ti∕Au Ohmic contacts on n-type bulk ZnO substrates are reported as a function of annealing temperature up to 450°C. A minimum contact resistivity of 4.6×10−6Ωcm2 was obtained at 50°C and the value remained <10−5Ωcm2 for all temperatures up to 450°C, suggesting that the Ti is an effective diffusion barrier which prevents formation of Au–In solid solutions. Optical microscopy of the contacts shows roughening of the morphology after annealing at 450°C. Indium outdiffusion to the surface of the contact stack is significant by 350°C, and Zn outdiffusion is evident by 450°C. Both the In and underlying Ti become oxidized after these higher temperature treatments.
Three-photon absorption in water-soluble ZnS nanocrystals
Authors: He Jun , Ji Wei , Mi Jun , Zheng Yuangang , Ying Jackie Y.
Published: May 2006

We report on large three-photon absorption (3PA) in glutathione-capped ZnS semiconductor nanocrystals (NCs), determined by both Z-scan and transient transmission techniques with 120fs laser pulses. The monodispersed, water-soluble ZnS NCs are synthesized by a modified protocol with a mean diameter of 2.5nm. Their 3PA cross section is determined to be ∼2.7×10−78cm6s2photon−2 at an optimal wavelength of commercial Ti:sapphire femtosecond lasers. This value is nearly one order of magnitude greater than that of CdS NCs, and four to five orders of magnitude higher than those of the previously reported common UV fluorescent dyes.
Semiconducting chalcogenide buffer layer for oxide heteroepitaxy on Si(001)
Authors: Schmidt D. A. , Ohta Taisuke , Lu C.-Y. , Bostwick Aaron A. , Yu Q. , Rotenberg Eli , Ohuchi F. S. , Olmstead Marjorie A.
Published: May 2006

We report controlled laminar growth of a crystalline transition metal oxide on Si(001) without SiOx or silicide formation by utilizing the chalcogenide semiconductor gallium sesquiselenide (Ga2Se3) as a nonreactive buffer layer. Initial nucleation of both pure and Co-doped anatase (TiO2) is along Ga2Se3 nanowire structures, coalescing to a flat, multidomain film within two molecular layers. Arsenic-terminated Si(001) [Si(001):As] is stable against pure O2, but oxidizes when both Ti and O2 are present. The Si–TiO2 valence band offset using either buffer layer is about 2.8eV, producing a staggered band alignment.
Electronic transport characteristics through individual ZnSnO3 nanowires
Authors: Xue X. Y. , Chen Y. J. , Li Q. H. , Wang C. , Wang Y. G. , Wang T. H.
Published: May 2006

Composite ZnSnO3 nanowires are synthesized via a one-step thermal evaporation method. The nanowires are of core-shell structures with the presence of grain boundary and out-of-phase boundaries. Transport through individual nanowires shows nonlinear current-voltage (I-V) characteristics in the range of the voltage from −3to3V. Such a behavior can be attributed to the presence of the barrier at the grain boundary, and the effective barrier height is estimated to be about 0.22eV by analyzing the I-V curves at various temperatures. The current at −3V jumps from 0.12to6.0μA within 30s at 300K as exposed to UV illumination. Such jump can be well explained in terms of effective barrier height and depletion width.
Development of photothermal-resistance technique and its application to thermal diffusivity measurement of single-wall carbon nanotube bundles
Authors: Hou J. , Wang X. , Liu C. , Cheng H.
Published: May 2006

In this work, a photothermal-resistance technique is developed to characterize the thermophysical properties of one-dimensional micro∕nanostructures. In this technique, a periodically modulated laser beam is used to achieve noncontact heating of suspended individual wires. The temperature response of the sample is monitored by measuring its electrical resistance variation. A 25.4μm thick platinum wire is used as the reference sample to verify the technique. Applying the photothermal-resistance technique, the thermal diffusivity of single-wall carbon nanotube bundles is measured. The measured thermal diffusivities for three different single-wall carbon nanotube bundles are 2.98×10−5, 4.41×10−5, and 6.64×10−5m2∕s, respectively. These values are much less than the thermal diffusivity of graphite.
Spiro-oxazine photochromic fiber optical switch
Authors: Huang Yanyi , Liang Wei , Poon Joyce K. S. , Xu Yong , Lee Reginald K. , Yariv Amnon
Published: May 2006

A photochromic all-optical switch in telecommunication-grade fiber is fabricated by filling a fiber Bragg grating Fabry-Pérot resonator with a spiro-oxazine solution. The narrow linewidth of the resonator allows for a high sensitivity of the resonance wavelengths to the index change. The switch is controlled by low intensity UV light exposure, and operation at infrared telecommunication wavelengths is demonstrated. The switching speed on the order of minutes has been achieved.
Anomalous dispersion measurement in terahertz frequency region by photomixing
Authors: Mouret G. , Matton S. , Bocquet R. , Bigourd D. , Hindle F. , Cuisset A. , Lampin J. F. , Lippens D.
Published: May 2006

Photomixing and coherent homodyne detection have been used to measure the absorption and dispersion of dielectric media. The signal to noise ratio was sufficient to allow the dispersion and absorption characteristics of a polytetrafluoroethylen (Teflon) sample to be extracted up to a frequency of 1.6THz. Due to the relatively narrow spectral linewidth of terahertz source, estimated to be in order of 5MHz, the anomalous dispersion in the vicinity of a rotational transition of carbonyl sulfide is clearly observed, with a refractive index variation of about 10−4 being measured at frequencies within 40MHz of the transition.
Tunneling spin polarization measurements from ferromagnet/MgO tunnel junctions using NbN superconductor
Authors: Yang Hyunsoo , Yang See-Hun , Kaiser Christian , Parkin Stuart
Published: May 2006

Superconducting aluminum electrodes have typically been used to measure the spin polarization of tunneling current using superconducting tunneling spectroscopy but at temperatures well below 1K. Using NbN superconducting electrodes we show that measurements at elevated temperatures (∼1.2K) are possible, thereby eliminating the need for the He3 dilution refrigerators. Tunneling spin polarization values can be extracted from the experimental data by fits using a strong coupling theory of the quasiparticle density of states of NbN. Nb and Ta electrodes were also explored but NbN, with its much lower spin-orbit scattering rate, yet higher superconducting transition temperature, is the most attractive.