bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevalence of transitional objects in young children in Tokyo and New York
Authors: Hobara Mieko
Published: March 2003

This study compared the prevalence of children's transitional object attachment in the two groups of young children in Tokyo and New York. The subjects (mothers of a child who was between two and four years of age) were 50 Caucasian women who resided in New York and 50 Japanese women who resided in Tokyo. Families of all subjects were within middle and upper socioeconomic status. There was a higher prevalence of transitional object attachment in American children (62%) than in Japanese children (38%). Japanese children more often slept in the same bed or same room with mothers than American children. The two groups did not differ regarding the hours of mother's availability. The results lend support to Gaddini and Gaddini's suggestion that children whose mothers are continuously available, especially at night, are not likely to develop attachment to transitional objects. The results from this survey research were discussed in terms of significance of transitional object attachment on child development. ©2003 Michigan Association for Infant Mental Health.
Clinical Interview for high‐risk Parents of premature infants (CLIP) as a predictor of early disruptions in the mother–infant relationship at the nursery
Authors: Keren Miri , Feldman Ruth , Eidelman Arthur I. , Sirota Leah , Lester Barry
Published: March 2003

The relations between mothers' narrative regarding the infant and the premature birth and the quality of mother–infant interaction were examined in mothers of 47 very low birth weight (<1650 g) premature singletons prior to discharge. Maternal representations were assessed with the Clinical Interview for high‐risk Parents of premature babies (CLIP), a semistructured interview that explores mothers' experiences of the pregnancy, delivery, hospitalization period, thoughts and feelings about the infant, and impending discharge. Ten minutes of mother–infant interaction were videotaped, and global and microanalytic codes were used to define three interactive variables: maternal adaptation, maternal touch, and infant withdrawal. Factor analysis of the CLIP items identified two factors with eigen values of 2.00 and above, termed Readiness for Motherhood and Maternal Rejection. Regression analyses were used to predict the three interactive variables by the infant's medical condition, maternal anxiety and depression, and the CLIP factors. Maternal adaptation to the infant's signal and maternal positive touch were each uniquely predicted by the mother's readiness for the maternal role, and were each negatively related to maternal depression. The infant's interactive withdrawal was independently predicted by maternal rejection. The clinical implications of the findings and the potential use of the CLIP for routine detection of early disruptions in the mother–infant relationship are discussed. ©2003 Michigan Association for Infant Mental Health.
Parenting after trauma: Supporting parents and caregivers in the treatment of children impacted by violence
Authors: Appleyard Karen , Osofsky Joy D.
Published: March 2003

The deleterious impact of trauma on parents and their capacity to parent their children seems well recognized in the clinical community, although not sufficiently studied empirically. The purposes of this article are to present an overview of current knowledge about trauma and parenting, to provide an illustrative clinical case study, and to offer recommendations for systemic treatment modalities, multidisciplinary program design, and empirical evaluation. The preponderance of evidence from both the available literature and clinical observations indicates the crucial need for caregiver support in families who have experienced violence. The case study provides an exemplar of the overlapping and interrelated clinical needs of families experiencing trauma. The authors conclude that future empirical study should focus on delineating the processes through which parent functioning following trauma affects children, as well as establishing the effectiveness of treatment and the links between improvement in parent mental health and subsequent enhanced functioning in children. ©2003 Michigan Association for Infant Mental Health.
Preparation and animal biodistribution of 166Ho labeled DOTA for possible use in intravascular radiation therapy (IVRT)
Authors: Das Tapas , Chakraborty Sudipta , Banerjee Sharmila , Samuel Grace , Sarma H. D. , Venkatesh Meera , Pillai M. R. A.
Published: March 2003

Owing to its favorable decay characteristics (T1/2=27 h, Eβ(max)=1.85 MeV, Eγ=81 keV) and its availability with a specific activity of 3.7–4.4 GBq/mg from a moderate flux reactor, 166Ho can be considered as a potential radionuclide for intravascular radiation therapy (IVRT) using liquid‐filled balloons. In the present work, studies on the use of 166Ho labeled 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (DOTA) as a possible agent for IVRT for the prevention of restenosis has been initiated. 166Ho was obtained by irradiating natural Ho2O3 powder and DOTA was synthesized by a multistep procedure. The optimum protocol of radiolabeling of DOTA with 166Ho was achieved by varying different reaction parameters. The complex was found to retain its stability for 7 days at room temperature. Bioevaluation studies carried out in Wistar rats showed that >95% of the injected activity was excreted within 3 h p.i. with almost no retention in any major organ. Both radiochemical and biological studies showed that 166Ho labeled DOTA can be further explored as a potential agent for IVRT. Copyright © 2002 John Wiley & Sons, Ltd.
Radiochemical stability of 14C‐compounds on storage: benefits of thioethers
Authors: Fredenhagen Andreas
Published: March 2003

Storage of radiochemicals is a significant practical problem. Storage as a solution in various solvents was compared to the storage as a neat oil or solid over an extended period of time. Dichloromethane, a solvent previously not recommended for storage, was found to be a good choice in certain solvent mixtures. Addition of methylsulfide or 2‐methyl‐2‐butene was shown to reduce the radiochemical decomposition by a factor of 1.7–3.2 in ethanol‐free solvents. General points to consider for storage of radiochemicals are discussed. Radiochemical purity was determined by HPLC. Copyright © 2002 John Wiley & Sons, Ltd.
Preparation of tritium‐labelled BIIL 260 of high specific radioactivity
Authors: Shevchenko V.P. , Nagaev I.Yu. , Myasoedov N.F. , Susan A.B. , Anderskewitz R. , Birke F.W. , Switek K‐H.
Published: March 2003

Various approaches to the synthesis of tritium‐labelled BIIL 260 with high specific radioactivity were investigated. Attempts to incorporate tritium directly into BIIL 260 were made by solid‐phase isotope exchange with tritium gas and by isotope exchange with tritiated water which yielded a final product with specific activities ranging from 2 to 7 Ci/mmol. However, the solid‐phase and liquid‐phase dehalogenations of an appropriate synthon fragment of BIIL 260 followed by its subsequent conversion to the final product via chemical synthesis yielded the desired tritium‐labelled BIIL 260 with specific activities of 25 or 71 Ci/mmol, depending upon the precursors and methods used in the dehalogenation step. Copyright © 2002 John Wiley & Sons, Ltd.
Preparation of labelled 2‐methoxy‐3‐alkylpyrazines: synthesis and characterization of deuterated 2‐methoxy‐3‐isopropylyrazine and 2‐methoxy‐3‐isobutylpyrazine
Authors: Gerritsma David A. , Brindle Ian D. , Jones Timothy R.B. , Capretta Alfredo
Published: March 2003

Efficient synthetic routes for a number of deuterated analogues of 2‐methoxy‐3‐isopropylpyrazines and 2‐methoxy‐3‐isobutylpyrazines have been developed involving the condensation of glyoxal with an α‐amino acid amide followed by methylation with iodomethane. In this way [2H3]2‐methoxy‐3‐isopropylpyrazine, 2‐methoxy‐3‐isopropyl‐[2H2]pyrazine, [2H3]2‐methoxy‐3‐isopropyl‐[2H2]pyrazine, [2H3]2‐methoxy‐3‐isobutylpyrazine; 2‐methoxy‐3‐isobutyl‐[2H2]pyrazine and [2H3]2‐methoxy‐3‐isobutyl‐[2H2]pyrazine were prepared and characterized by NMR and MS. Copyright © 2002 John Wiley & Sons, Ltd.
Methylation of the thiophene ring using Carbon‐11‐labelled methyl iodide: formation of 3‐[11C]methylthiophene
Authors: Karramkam M. , Demphel S. , Hinnen F. , Trognon C. , Dollé F.
Published: March 2003

This paper describes the radiosynthesis of 3‐[11C]methylthiophene, chosen as a model reaction for the preparation of heteroaromatic methylthienyl compounds. Labelling was performed from the corresponding lithiothiophene derivative and [11C]methyl iodide as the alkylating agent in THF at −78°C. The conditions used were the following: (1) trapping for 2–3 min at −78°C of the [11C]methyl iodide in the THF solution containing the freshly prepared 3‐lithiothiophene; (2) Hydrolysis of the reaction mixture by adding 0.5 ml of the HPLC mobile phase and (3) HPLC purification. 3‐[11C]Methylthiophene ([11C]‐1) was collected in high yield as the unique peak of the HPLC radiochromatogram. Non‐reacted [11C]methyl iodide was not present. Typically, 50–60 mCi (1.85–2.22 GBq) of 3‐[11C]methylthiophene ([11C]‐1) were obtained within 20 min of radiosynthesis (including HPLC purification) with specific radioactivities ranging from 0.6 to 1.0 Ci/μmol (22.2–37.0 GBq/μmol) starting from 180 to 200 mCi (6.66–7.40 GBq) of [11C]CO2 (10 μA, 10 min (6000 μC) irradiation). Copyright © 2002 John Wiley & Sons, Ltd.
Computational screening of branched cyclic peptide motifs as potential enzyme mimetics
Authors: Stavrakoudis Athanassios , Makropoulou Sevasti , Tsikaris Vassilios , Sakarellos‐Daitsiotis Maria , Sakarellos Constantinos , Demetropoulos Ioannis N.
Published: March 2003

In a previous work we described the design, synthesis and catalytic activity of a branched cyclic peptide as a serine protease mimic. To maximize its catalytic activity we present now a systematic search of a large number of homologous peptides for potential enzyme activity as revealed by the topological arrangement of the catalytic triad residues. This process is accomplished by applying a combined molecular mechanics and molecular dynamics conformational search of about 200 molecules. Starting from a previously synthesized compound that showed some hydrolytic activity several analogues were modelled by amino acid substitutions in the main molecular framework using the Insight II molecular modelling environment with some script automation. Also presented is an algorithm that: (a) generates all possible combinations of residue substitutions, (b) scans the conformational space for each molecule via high temperature molecular dynamics, (c) picks the set of molecules the trajectories of which retained, to a considerable degree, the catalytic triad molecular arrangement, (d) subjects the selected molecules to layer solvation and energy minimization and chooses the molecules, the conformations of which could preserve the catalytic triad arrangement. Finally, a modelling with periodic boundary conditions, was performed to further support the reported algorithm. We found that at least one of the analogues could be a potential serine protease mimic, as revealed by the root‐mean‐square comparison between the catalytic triad in two molecular dynamics trajectories of the peptide and the corresponding residues in the crystal structure of trypsin. The most promising model candidate was synthesized and tested for its catalytic activity. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Effect of pH on the aggregate formation of a non‐amyloid component (1–13)
Authors: Abe Hiroshi , Nakanishi Hiroshi
Published: March 2003

The formation of aggregates including amyloid fibrils in the peptide fragment of non‐amyloid‐β component (NAC(1–13)) was investigated under a variety of solution conditions. Two types of sample preparation method from neutral and acidic conditions were examined. Electron microscopy observation showed amorphous aggregates in the sample at pH 4.5 adjusted from the neutral condition. The CD and HPLC quantitative analyses indicated that the formation of the amorphous aggregate did not accompany a conformational conversion from a random coil in the sample solution. The analyses of pKa values determined by pH titration experiments in NMR spectroscopy indicated that the protonation of the carboxyl group of the N‐terminal glutamic acid triggers the aggregation of NAC(1–13). On the other hand, electron microscopy observation showed that the samples at pH 2.2 and 4.5 adjusted from an initial pH of 2.2 form fibrils. A β‐structure was detected by CD spectroscopy in the 1 mM NAC(1–13) at pH 2.2 immediately after preparation. The CD analyses of samples at different concentrations and temperatures indicated that 1 mM NAC(1–13) immediately after preparation at pH 2.2 was oligomerized. The quantity of the β‐structure was increased depending on the incubation time. The results strongly suggested that the β‐conformational oligomers play a critical role for the fibril nucleus. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Efficacy of Adcon-T/N After Primary Flexor Tendon Repair in Zone II: A Controlled Clinical Trial
Authors: GOLASH A. , KAY A. , WARNER J. G. , PECK F. , WATSON J. S. , LEES V. C.
Published: March 2003

A prospective double-blind, randomized, controlled clinical trial was conducted to assess the use of ADCON-T/N after flexor tendon repair in Zone II. Forty-five patients with 82 flexor tendon repairs in 50 digits completed the study. ADCON-T/N was injected into the tendon sheath after tenorrhaphy in the experimental group while the control group was not treated with ADCON-T/N. ADCON-T/N had no statistically significant effect on total active motion at 3, 6 and 12 months but the time taken to achieve the final range of motion was significantly shorter in treated patients. ADCON-treated patients had a higher rupture rate but this was not significant.
Dynamic External Fixator for Pilon Fractures of the Proximal Interphalangeal Joints: A Simple Fixator for A Complex Fracture
Authors: SYED A. A. , AGARWAL M. , BOOME R.
Published: March 2003

We describe a very cheap, simple and effective dynamic external fixator for treatment of pilon fractures of the proximal interphalangeal joint. At final follow-up, nine such fractures had regained an average range of motion of 79° (range, 65–90°). There was high patient satisfaction and there were no serious complications.
Spontaneous and experimental osteoarthritis in dog: Similarities and differences in proteoglycan levels
Authors: Liu Wenhua , Burton‐Wurster Nancy , Glant Tibor T. , Tashman Scott , Sumner Dale R. , Kamath Rajesh V. , Lust George , Kimura James H. , Cs‐Szabo Gabriella
Published: March 2003

The unilateral canine model is the most commonly used model of experimental osteoarthritis (OA). In this model, the anterior cruciate ligament (ACL) of one knee is transected and the contralateral joint is usually used as a control. However, dogs, similar to humans, can develop OA spontaneously with old age. Additionally, certain breeds of dogs are genetically predisposed to OA and can develop symptoms at a young age. The goal of this study was to compare the pathological changes of proteoglycans in OA cartilage from dogs that developed OA spontaneously to those that underwent ACL transection. For this reason, biglycan, decorin and fibromodulin levels and degradation patterns were compared by Western blot hybridization, and aggrecan contents were quantified by dimethylmethylene blue assay. The changes in proteoglycan levels in the cartilage of dogs with spontaneous OA, regardless of their age, were very similar to those published for human OA cartilage. However, when OA developed as a result of ACL‐surgery, the changes in proteoglycans were different from those of slowly developing spontaneous OA. Therefore, these differences should be taken into consideration when the ACL‐transection model is used. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Maple syrup urine disease: Mutation analysis in Turkish patients
Authors: Dursun A. , Henneke M. , Özgül K. , Gartner J. , Coşkun T. , Tokatli A. , Kalkanoğlu H. S. , Demirkol M. , Wendel U. , Özalp İ.
Published: March 2003

Maple syrup urine disease (MSUD), the most frequently occurring organic acidaemia in Turkey, is caused by a deficiency of the activity of branched‐chain keto acid dehydrogenase enzyme (BCKAD) complex. Mutation analysis of the E1α, E1β, and E2 genes of the BCKAD complex in 12 Turkish MSUD patients yielded three disease‐specific mutations and a polymorphism in the E1α gene, none in the E1β gene and one mutation in the E2 gene. Among them, three missense mutations (Q80E, C213Y, T106M) and the F280F polymorphism occurring in the E1α gene and the splice site mutation (IVS3 − 1G > A) in the E2 gene were novel. Three of the missense mutations and the splicing mutation occurred homozygously and caused classical MSUD. One patient carried the splicing mutation homozygously and the T106M mutation in the heterozygous state; this patient is the first case having simultaneously two different mutations in two different genes in the BCKAD complex. IVS3 − 1G > A splicing mutation detected on the E2 gene causes deletion of the first 14 bp of exon 3 in the mutant mRNA extending between 190 and 204 nt. The deletion spans the cleavage point between mitochondrial targeting and lipoyl‐bearing site of the E2 protein.
Towards a New Role for Occupational Pensions in Continental Europe: Elements and Techniques of Solidarity Used within Funded Occupational Pension Schemes
Authors: Stevens Yves , Gieselink Gerhard , Van Buggenhout Bea
Published: March 2003

‘At first glance, it may seem incongruous to talk of private pensions in terms of equity. We do not for example, question whether champagne consumption is fairly distributed.’

This paper is about the debate on occupational pensions in continental Europe. Instead of looking at the financial issues, it looks at the elements of social protection and solidarity within occupational pensions. Occupational pensions are of increasing importance for continental European society. This is indicated by a so-called ‘new pension order’ that is predominantly influenced by the Anglo-Saxon vision of pensions. However, much of the ongoing (legal) debate on pension reform deals with elements such as fairness and redistribution.
PEG-Immunoliposome
Authors: Maruyama Kazuo
Published: March 2003

This review deals with the current status of newly developed pendant-type PEG-immunoliposomes (Type C), carrying monoclonal antibodies or their fragments (Fab') at the distal ends of the PEG chains. In terms of target binding of Type C, two different anatomical compartments are considered. They are mouse lung endothelium as a readily accessible site via the intravascular route and the implanted solid tumor as a much less accessible target site reached via extravasation. Small unilamellar liposomes (90–130 nm in diameter) were prepared from phosphatidycholine and cholesterol (2:1, m/m) containing 6 mol.% of DSPE-PEG-COOH or DPPE-PEG-Mal. For targeting to the vascular endothelial surface in the lung, 34A antibody, which is highly specific to mouse pulmonary endothelial cells, was conjugated to PEG-liposomes (34A-Type C). The degree of lung binding of 34A-Type C in BALB/c mouse was significantly higher than that of 34A-Type A, which is an ordinary type of immunoliposome (without PEG derivatives). For targeting to solid tumor tissue, 21B2 antibody (anti-human CEA) and its Fab' fragment were used. The targeting ability of Fab'-Type C was examined by using CEA-positive human gastric cancer strain MKN-45 cells inoculated into BALB/c nu/nu mice. Fab'-Type C showed low RES uptake and a long circulation time, and enhanced accumulation of the liposomes in the solid tumor was seen. The small Fab'-Type C predominantly passed through the leaky tumor endothelium by passive convective transport. These studies offer important insights into the potential of Type C liposomes for target-specific drug delivery.
Plasmid Delivery in the Rat Brain
Authors: Hirko A.C. , Buethe D.D. , Meyer E.M. , Hughes J.A.
Published: March 2003

Neurodegenerative diseases as a class do not have effective pharmacotherapies. This is due in part to a poor understanding of the pathologies of the disease processes, and the lack of effective medications. Gene delivery is an attractive possibility for treating these diseases. For the paradigm to be effective, efficient, safe and versatile vectors are required. In this study we evaluated three plasmid delivery systems for transgene expression in the rat hippocampus. Two of these systems were designed to have enhanced intracellular biodegradability. It was hypothesized that this system would be less toxic and could increase the free (non-vector) associated plasmids within the cell, leading to increased transgene activity. Polyethylenimine (PEI) and r-AAV-2 (recombinant adeno associated virus-2) were used as positive, non-viral and viral controls respectively, in the in vivo experiments. The results from the studies indicate there is a distinct difference between the various vectors in terms of total cells transfected, type of cell transfected, and toxicity. Non-viral systems were effective at transfecting both neurons and glia cells within the hippocampus, while the r-AAV-2 transfected mainly neurons. In summary, plasmid-mediated systems are effective for transgene expression within the brain and deserve further study.
Das Verhalten des Busfahrpersonals und die wahrgenommene Dienstleistungsqualität
Authors: Buhbe Andreas , Schlag Bernhard
Published: March 2003

Zusammenfassung. Um den Beitrag der Busfahrerinnen und Busfahrer im Öffentlichen Personennahverkehr (ÖPNV) an der wahrgenommenen Qualität der Dienstleistung zu analysieren, wurde ein von Runde und Schnippe (1997) entwickeltes Messinstrument, welches elf Qualitätskriterien umfasst, um die verhaltensrelevanten Qualitätskriterien “Persönlicher Schutz“ und “Angenehmes Erscheinungsbild“ ergänzt. Den Befragten wurde ein Urteil bezüglich der tatsächlichen und der gewünschten Ausprägung der Merkmale und ihrer Wichtigkeit abverlangt. Von insgesamt 1500 im Januar 1998 in Zusammenarbeit mit einem öffentlichen Verkehrsbetrieb verteilten Fragebögen wurden 391 zurückgesandte Exemplare ausgewertet. Insgesamt führt das eingesetzte Instrument zu aussagestarken Ergebnissen. Die Merkmale “Pünktlichkeit“, “Verkehrssicheres Verhalten“, “Freundlichkeit“ und “Hilfsbereitschaft“ sind den Kunden insgesamt am wichtigsten. Mittels einer konfirmatorischen Faktorenanalyse sind die dreizehn Merkmale auf drei Faktoren verdichtet worden. Dabei handelt es sich um die Konstrukte “Kundenfreundliches Verhalten“, “Fahrweise“ und “Ordnung & Sauberkeit“. Die beiden zusätzlichen Qualitätskriterien “Persönlicher Schutz“ und “Angenehmes Erscheinungsbild“ konnten der Dimension “Ordnung und Sauberkeit“ zugeordnet werden, welche nun treffender in “Sorgsamkeit“ umbenannt wurde.
Standards for Internet-Based Experimenting
Authors: Reips Ulf-Dietrich
Published: March 2003

This article summarizes expertise gleaned from the first years of Internet-based experimental research and presents recommendations on: (1) ideal circumstances for conducting a study on the Internet; (2) what precautions have to be undertaken in Web experimental design; (3) which techniques have proven useful in Web experimenting; (4) which frequent errors and misconceptions need to be avoided; and (5) what should be reported. Procedures and solutions for typical challenges in Web experimenting are discussed. Topics covered include randomization, recruitment of samples, generalizability, dropout, experimental control, identity checks, multiple submissions, configuration errors, control of motivational confounding, and pre-testing. Several techniques are explained, including “warm-up,” “high hurdle,” password methods, “multiple site entry,” randomization, and the use of incentives. The article concludes by proposing sixteen standards for Internet-based experimenting.
Rape Myth Acceptance and Judgments of Vulnerability to Sexual Assault: An Internet Experiment
Authors: Bohner Gerd , Danner Unna N. , Siebler Frank , Samson Gary B.
Published: March 2003

Processing strategies in risk assessment were studied in an Internet experiment. Women (N = 399) who were either low or high in rape myth acceptance (RMA) were asked to recall either two or six behaviors that either increase or decrease the risk of being sexually assaulted. Later they judged their personal vulnerability to sexual assault under either no time pressure (no response deadline) or time pressure (response deadline of 5 s). Without time pressure, the results were opposite to previous research: Women low in RMA relied on ease of recall and reported higher vulnerability after recalling few rather than many risk increasing behaviors, or many rather than few risk-decreasing behaviors; women high in RMA relied on the amount of information recalled, which resulted in an opposite pattern of vulnerability judgments. No influences of ease of recall or amount recalled on vulnerability judgments were detected under time pressure.
Hindsight Bias Around the World
Authors: Pohl Rüdiger F. , Bender Michael , Lachmann Gregor
Published: March 2003

Hindsight bias refers to the tendency to overestimate in hindsight what one has known in foresight. Recently, two experiments extended the research to include samples from different cultures ( Choi & Nisbett, 2000 ; Heine & Lehman, 1996 ). Asking their participants what they would have guessed before they knew the outcome (“hypothetical design”), Choi and Nisbett (2000 ) found that Koreans, in comparison to North Americans, exhibited more hindsight bias. Heine and Lehman (1996 ), however, reported that Japanese people in comparison to Canadians showed marginally less hindsight bias. In a second study, in which participants were asked to recall what they had estimated before they knew the outcome (“memory design”), the latter authors found no difference in hindsight bias between Japanese people and Canadians. We extended these studies with 225 Internet participants, in a hypothetical design, from four different continents (Asia, Australia, Europe, and North America). Hindsight bias was large and similar for all samples except for German and Dutch participants who showed no hindsight bias at all. While the latter effect may be based on peculiarities of the material and of the participants, the former underscores the worldwide stability of the phenomenon. In addition a follow-up surprise rating (paper and pencil) in China (35 participants) and Germany (20 participants) revealed that only less surprising items led to hindsight bias while more surprising ones did not. We suggest that the basic cognitive processes leading to hindsight bias are by-products of the evolutionary-evolved capacity of adaptive learning. On top of these basic processes, individual meta-cognitions (e.g., elicited by surprise) or motives (e.g., a self-serving motive) may further moderate the amount of bias, thus explaining the diverging results of Choi and Nisbett (2000 ), Heine and Lehman (1996 ), and our own study.
Measuring Differences in Preactivation on the Internet: The Content Category Superiority Effect
Authors: Eichstaedt Jan
Published: March 2003

Preactivation of particular content categories in memory yields latency differences in a visual recognition task. Two Internet studies demonstrate this content category superiority effect (CCSE). Target words are repeatedly flashed for 400 ms and then masked for 200 ms. Experiment 1 shows that differences in pre-activated memory content, related to participants’ use of computer operating systems, influence z-scored visual word recognition latencies. Experiment 2 shows that this influence is susceptible to instruction. Participants expecting to find positive words recognized those words faster, whereas participants expecting to find negative words were faster on negative words. The CCSE provides a basis on which new measures of implicit memory content can be founded. Two such applications are discussed - the Motive Superiority Measure of implicit motives, and a latency-based measure of self-focused attention.
Internet Experts’ Planning of Explanations for Laypersons: A Web Experimental Approach in the Internet Domain
Authors: Nückles Matthias , Bromme Rainer
Published: March 2003

How flexible are Internet experts in taking the perspective of laypersons? A Web experimental approach is presented that examines the Internet experts’ perspective taking in planning explanations for laypersons. The Internet was the topic to be communicated and it also provided the means to implement the experimental method. Participants rated how extensively they would treat some specific concepts when explaining a topic such as the WWW. Independent variables were the addressee’s intention, their level of domain knowledge, and the importance of the concepts to be evaluated. The results show that the experts preferred planning strategies that integrated all three types of information. Though their planning decisions were mainly guided by conceptual constraints, the Internet experts also took into account information about the addressee’s intention and prior knowledge.
Temperature dependence of lithium ion solvation in ethylene carbonate–LiClO4 solutions
Authors: Castriota Marco , Cazzanelli Enzo , Nicotera Isabella , Coppola Luigi , Oliviero Cesare , Ranieri Giuseppe Antonio
Published: March 2003

The solvation mechanism of lithium ions in pure ethylene carbonate (EC) solutions has been studied in a wide concentration range by different techniques and for temperatures up to 100 °C. For low concentrations (R=[Li+]/[EC]⩽0.1) the solvation number of Li+ cations in the solution has been found to be ∼7, by using nuclear magnetic resonance techniques. This number decreases at higher concentration, and complexes Li+-EC with ∼3 solvent molecules per cation are formed when R=0.33. The temperature dependence of the solvation has been investigated for the more concentrated solutions by Raman spectroscopy. When the temperature increases, the relative intensity of the Raman bands upshifted by the lithium interaction also increases remarkably, indicating that Li+ ions form complexes with a higher solvation number. On the other hand, a higher degree of reassociation of Li+ cations with perchlorate anions is observed.
The crystalline surfaces of β-PdH{111}: Ideal surface terminations of a stoichiometric bulk compound relevant to heterogeneous catalysis
Authors: Pérez Jigato Manuel , Coussens Betty , King David A.
Published: March 2003

The surface chemistry of β-PdH{111} is of paramount importance as evidenced by the presence of the binary compound in the bulk of Pd catalytic particles during high pressure hydrogenation processes occuring at the industrial scale. Furthermore, the {111} plane is the most frequently exposed surface by the catalyst. A systematic study is herein performed which involves the computation of surface structure, workfunction, strain derivative of the surface energy, surface free energy and H binding energy for three surface terminations characterized as H-terminated, Pd-terminated and H-vacancy terminated β-PdH{111}, by means of a plane-waves pseudopotential electronic structure algorithm. Further results of partial and local density of states, Mulliken charges and local isoelectronic softness complete a full characterization of the physical and chemical properties, which, for the first time are presented for the β-PdH{111} surface using the predictive power of density functional theory.
Variable reaction coordinate transition state theory: Analytic results and application to the C2H3+H→C2H4 reaction
Authors: Georgievskii Yuri , Klippenstein Stephen J.
Published: March 2003

A novel derivation is provided for the canonical, microcanonical, and energy E and total angular momentum J resolved reactive flux within the variable reaction coordinate transition state theory (VRC-TST) formalism. The use of an alternative representation for the reaction coordinate velocity yields a new expression for the kinematic factor which better illustrates its dependence on the pivot point location, and which can be straightforwardly evaluated. Also, the use of a geometric approach in place of an earlier algebraic one clarifies the derivation as does the use of Lagrange multiplier methodology for the analytic integration over the total angular momentum. Finally, a quaternion representation for the fragment and line-of-centers orientations is employed in place of the Euler angle or internal/external rotational coordinates used in prior studies. The result is an efficient, and particularly easy to implement, methodology for performing variable reaction coordinate transition state theory calculations. Furthermore, the simplicity of the derivation allows for the straightforward generalization to alternative forms for the dividing surface, as is illustrated by deriving the expressions for the cases of elliptical and planar dividing surfaces. Application to the C2H3+H reaction yields results for the total rate coefficient that are generally only 15% greater than those obtained from related trajectory simulations, thereby demonstrating the accuracy of the VRC-TST formalism. Meanwhile, results for the two separate addition channels (frontside and backside) illustrate the difficulty of accurately apportioning the total flux and particularly the inadequacy of canonical predictions for the channel specific optimized dividing surfaces.
High-performance TaN/HfSiON/Si metal-oxide-semiconductor structures prepared by NH3 post-deposition anneal
Authors: Akbar Mohammad Shahariar , Gopalan S. , Cho H.-J. , Onishi K. , Choi R. , Nieh R. , Kang C. S. , Kim Y. H. , Han J. , Krishnan S. , Lee Jack C.
Published: March 2003

Electrical and chemical characteristics of metal-oxide semiconductor field-effect transistors (MOSFETs) prepared by low-thermal-budget (∼600 °C) NH3 post-deposition annealing of HfSiON gate dielectric have been investigated. Compared to control Hf-silicate, HfSiON showed excellent thickness scalability, low leakage current density (J), and superior thermal stability. With proper annealing-time optimization, effective oxide thickness as low as 9.2 Å with J<100 mA/cm2 at gate voltage Vg=−1.5 V has been achieved. C–V hysteresis of HfSiON MOSFET was found to be small (<20 mV). Unlike NH3 surface nitridation (NH3 pre-treatment prior to Hf-silicate deposition), no degradation in Gm (transconductance), Id–Vg (drain current–gate voltage), or Id–Vd (drain current–drain voltage) characteristics has been observed.
Electronic structure of electrochemically Li-inserted TiO2 studied with synchrotron radiation electron spectroscopies
Authors: Henningsson Anders , Rensmo Håkan , Sandell Anders , Siegbahn Hans , Södergren Sven , Lindström Henrik , Hagfeldt Anders
Published: March 2003

The electronic properties of TiO2 and electrochemically Li-inserted TiO2 have been studied using synchrotron radiation photoelectron spectroscopy and x-ray absorption spectroscopy (XAS) in conjunction with resonant photoelectron spectroscopy. Core level (Ti 2p) and valence level spectra show the presence of Ti3+ states in LixTiO2. The x values determined from core level peak intensities were found to be directly correlated to the inserted amount of Li+ determined electrochemically. The x-dependent width of the Ti 2p peaks is consistent with a two-phase regime at intermediate x values. Resonant photoelectron spectroscopy at the Ti 2p edge was performed for TiO2 and Li0.5TiO2 to delineate the Ti4+ and Ti3+ contributions to the XAS spectrum.
Contribution of colliding parallel electron spins to electron paramagnetic resonance spectral narrowing
Authors: Kolbasov Dmitri , Norris James R.
Published: March 2003

Interactions between two colliding spin-one-half radicals with nearly parallel Z projections are considered in the case of strong Heisenberg spin exchange. The average value of the transverse spin polarization is shown to distribute equally between interacting radicals after the collisions. This is equivalent to the exchange of the polarization in 50% of the collisions. Collisions between parallel spins are shown not to represent a kinetic bottleneck when spectral narrowing follows from electron spin exchange. Thus, in applying the Kubo–Anderson model to the system of interacting radicals, every spin collision, regardless of spin orientation, results in random movement among various sites of different resonant frequencies and thus to spectral narrowing. We conclude that limiting discussions of spin exchange to antiparallel spins and mutual spin flips may lead to a false impression of spin dynamics and spectral narrowing by Heisenberg spin exchange.
Front and back instability of a liquid film on a slightly inclined plate
Authors: Thiele Uwe , Knobloch Edgar
Published: March 2003

We study the transverse instability of a liquid ridge on horizontal and inclined substrates using a film evolution equation based on a long wave approximation. The equation incorporates an additional pressure term—the disjoining pressure—accounting for the effective interaction of the film with the substrate. On a horizontal substrate the dominant instability mode is varicose, but may turn into a zigzag mode on a slightly inclined substrate depending on the inclination angle and the ridge volume. For larger angles or volumes the instabilities at the front and back decouple. The linear stability properties of a one-dimensional transverse ridgelike state are studied in detail, and an energy analysis is used to demonstrate that the disjoining pressure provides the dominant instability mechanism at both the front and the back, while the body force is responsible for the main differences between these two instabilities. An amplitude equation for the time evolution of perturbations with small transverse wave numbers is derived that predicts correctly the linear crossing of the most dangerous eigenvalues at zero wave number in the inclined case, in contrast to the situation on a horizontal substrate.
Time-resolved kinetic studies on quenching of NCO (A 2Σ+) by alkanes and substituted methane molecules
Authors: Hu Changjin , Zhu Zhiqiang , Pei Linsen , Ran Qin , Chen Yang , Chen Congxiang , Ma Xingxiao
Published: March 2003

NCO radicals were produced by laser photolysis of CHBr3 at 266 nm followed by the reaction of CH with N2O. The radicals were then electronically excited from the ground electronic state to the A 2Σ+ state with a Nd:YAG laser pumped dye laser at 438.6 nm in the Q subband of A 2Σ+(0000)←X 2Πi(0010). The rate constants kq and thermally averaged cross sections σq for collision quenching of NCO (A 2Σ+) by n-CnH2n+2 (n=1,5–8), c-C6H12, CH4−nCln (n=1–4), CH3OH, CH3NO2, and CCl2F2 were measured at room temperature (298 K) by observing the time-resolved fluorescence signals of the excited NCO in a cell at total pressure of about 20 Torr. Formation cross sections of complexes of the electronically excited NCO radicals and quenchers were calculated by means of a collision complex model. It was shown that the quenching rates of NCO (A 2Σ+) by alkane molecules increase with the number of C–H bonds of the molecules, and that the attractive forces play a main role in the collisional quenching processes of NCO (A 2Σ+) by the quenchers studied in this work.
Surface tension of a square well fluid
Authors: Orea Pedro , Duda Yurko , Alejandre José
Published: March 2003

We performed Monte Carlo simulations in the canonical ensemble on the liquid–vapor interface of a square well fluid with interaction range of λ=1.5σ. The system contains a liquid slab surrounded by vapor. The surface tension is calculated during simulations by using an original procedure that allows the calculation of the pressure tensor components. The surface tension decreases monotonically with temperature. Coexisting densities and pressure along the liquid–vapor coexistence line have also been obtained and good agreement is found with results calculated from bulk simulations.
Time-dependent discrete variable representation method in a tunneling problem
Authors: Barkakaty Balaka , Adhikari Satrajit
Published: March 2003

We have investigated the dynamics of a reaction coordinate with or without coupling to a heat bath of harmonic oscillators using a novel time-dependent discrete variable representation (TDDVR) method. The proposed method is semiclassical in nature, theoretically rigorous, and rather straightforward to implement. Excellent agreement of the computed tunneling probabilities and time-averaged tunneling rates with the corresponding exact results demonstrates the efficacy of the proposed approach. Most of the semiclassical calculations reported here have been performed by using classical force, whereas, in a few cases, the quantum force (QF) has been taken into account. It appears that among the TDDVR formulations, it was the first time we have derived a rigorous form of QF from the first principle.
Interbasin motion approach to dynamics of conformationally constrained peptides
Authors: Despa Florin , Fernández Ariel , Berry R. Stephen , Levy Yaakov , Jortner Joshua
Published: March 2003

In this paper, the interbasin motion (IBM) approach is applied to studying dynamics of conformationally constrained peptides, being extended to a nonideal contact of the system with a thermal bath. The coupling of the system with the thermal bath is expressed in terms of a memory function. The aim of the present study is twofold. First, we present a dynamical diagnosis of the three hexapeptide variants with the main focus on the transitions between basins rather than between individual states. Second, the present study is intended to pinpoint a way for extracting useful information about the strength of the system–solvent coupling and how this interaction affects the propensity of relaxation towards the native state. We show that a slight variation of the value of the memory friction parameter may induce a sizable modification of the relaxation time. In addition, the change of the memory friction parameter produces alterations on short time scales among the population distributions. Especially, high energy basins seem affected the most. In the Markovian limit, the basin populations computed within the IBM model are compared to those obtained by using state-to-state transition rates in the full master equation approach. The two methods yield similar results when the separation of time scales between intra- and interbasin dynamics is completely achieved.
Free energy and size distributions of micelles in solution
Authors: Christopher P. S. , Oxtoby David W.
Published: March 2003

This paper presents a new derivation of the free energy of micellar solutions. From this free energy a micelle size distribution can be calculated. By using a density functional model for the bulk contribution to the free energy, and a simple approximation for the micelle (proper) contribution, we develop a simple, tractable model for the free energy of micellar solutions. We also explore the relationship of our model to the standard thermodynamic models used to study micellar solutions. We present model calculations using combinatorial minimization of the free energy, paying particular attention to entropic effects on the micelle size distribution.
Vibrational relaxation of CH2I2 in solution: Excitation level dependence
Authors: Elles Christopher G. , Bingemann Dieter , Heckscher Max M. , Crim F. Fleming
Published: March 2003

Transient electronic absorption monitors the flow of vibrational energy in methylene iodide (CH2I2) following excitation of five C–H stretch and stretch–bend modes ranging in energy from 3000 to 9000 cm−1. Intramolecular vibrational relaxation (IVR) occurs through a mechanism that is predominantly state-specific at the C–H stretch fundamental but closer to the statistical limit at higher excitation levels. The IVR times change with the excitation energy between the fundamental and first C–H stretch overtone but are constant above the overtone. The intermolecular energy transfer (IET) times depend only weakly on the initial excitation level. Both the IVR and the IET times depend on the solvent [CCl4, CDCl3, C6D6, C6H6, or (CD3)2CO] and its interaction strength, yet there is no energy level dependence of the solvent influence.
Analysis of heat transfer from single wires close to walls
Authors: Shi J.-M. , Gerlach D. , Breuer M. , Durst F. , Lange C. F.
Published: March 2003

Two-dimensional numerical investigations of the forced heat convection from a microcylinder in laminar cross-flow, both in free stream and in near-wall flow, were carried out aiming at a better understanding of the physics behind the wall effects on hot-wire near-wall measurements. In the physical model, an infinitely thin plate with the same properties as the fluid (air) was used as an artificial wall. The conjugate heat transfer between the flow regions on both sides of the plate was taken into account. The effect of the conjugate thermal conditions (temperature distribution and diffusive heat flux) at the interface of the two flow regions on the heat transfer from the wire was investigated by varying the flow conditions on the side opposite to the wire location. Careful energy balance analysis was performed for both the free-stream case and the near-wall case. This enabled the authors to verify their own understanding of the physical mechanism responsible for the wall effect on hot-wire measurements and to examine other mechanisms proposed in the literature. The numerical results showed that the heat diffusion from the wire is significantly enhanced in the case of small wire-to-wall distances (Y+<3). This is mainly caused by modifications of the thermal boundary condition (diffusive effect) at the fluid–wall interface. In contrast, the flow distortion (enhanced convection) was shown not to be the most important influencing factor for the heat transfer of a hot wire. Although the present model study was performed for a laminar flow, the results obtained are applicable to hot-wire measurements in turbulent flows, as stated in the literature.
Zeeman spectra of the Ã 1Au←X̃ 1Ag transition of trans-glyoxal studied by Doppler-free two-photon fluorescence excitation spectroscopy
Authors: Misono Masatoshi , Wang Jin Guo , Katô Hajime , Baba Masaaki
Published: March 2003

Doppler-free two-photon fluorescence excitation spectra of the Ã 1Au(v7′=1)←X̃ 1Ag(v″=0) transition of trans-glyoxal were measured by propagating a laser beam either polarized parallel (π pump) or perpendicular (σ pump) to the magnetic field of 6 T. π pump and σ pump dependence of the Zeeman spectra of the Q(J=6)Q(K) lines for K=0–6 was measured. Intensities of the Zeeman components of the Q(6)Q(6) lines were observed to have the maxima at the high and low wave number ends and the minimum at the middle for π pump, and the minima at the high and low wave number ends and the maximum at the middle for σ pump. By comparing calculated and observed patterns of the Zeeman spectra, it became clear that the transition tensor M00 is dominant and the effective intermediate state is 1 1Bu(ππ*). K dependence of the Zeeman spectra of the Q(J=15)Q(K) lines was measured, and the Zeeman splittings were observed to increase proportionally to K2. J dependence of the Zeeman spectra of the Q(J)Q(K=J) lines was measured for J=0–15, and the Zeeman splittings was found to increase proportionally to J. The K and J dependence of the Zeeman splittings were analyzed. It is concluded that the Zeeman splitting of the Ã 1Au(nπ*) state is originating from the mixing of the 1 3Bu(ππ*) state by spin–orbit interaction, and the magnetic moment is along the molecular top axis.