bluuebunny/crossref_metadata_2025 huggingface dataset:
Systematic identification and integrative analysis of novel genes expressed specifically or predominantly in mouse epididymis
Authors: Oh Jungsu , Lee Jiae , Woo Jong-Min , Choi Eunyoung , Park Inju , Han Cecil , Baek Namhoe , Lee Hoyong , Kim Do Han , Cho Chunghee
Published: December 2006

Background

Maturation of spermatozoa, including development of motility and the ability to fertilize the oocyte, occurs during transit through the microenvironment of the epididymis. Comprehensive understanding of sperm maturation requires identification and characterization of unique genes expressed in the epididymis.

Results

We systematically identified 32 novel genes with epididymis-specific or -predominant expression in the mouse epididymis UniGene library, containing 1505 gene-oriented transcript clusters, byin silicoandin vitroanalyses. The Northern blot analysis revealed various characteristics of the genes at the transcript level, such as expression level, size and the presence of isoform. We found that expression of the half of the genes is regulated by androgens. Further expression analyses demonstrated that the novel genes are region-specific and developmentally regulated. Computational analysis showed that 15 of the genes lack human orthologues, suggesting their implication in male reproduction unique to the mouse. A number of the novel genes are putative epididymal protease inhibitors or β-defensins. We also found that six of the genes have secretory activity, indicating that they may interact with sperm and have functional roles in sperm maturation.

Conclusion

We identified and characterized 32 novel epididymis-specific or -predominant genes by an integrative approach. Our study is unique in the aspect of systematic identification of novel epididymal genes and should be a firm basis for future investigation into molecular mechanisms underlying sperm maturation in the epididymis.
Over-diagnosis of malaria is not a lost cause
Authors: Masika Paul M , Semarundu Waziri J , Urassa Raymond , Mosha Jackline , Chandramohan Daniel , Gosling Roly D
Published: December 2006

Background

Recent studies have highlighted the over-diagnosis of malaria in clinical settings in Africa. This study assessed the impact of a training programme implemented as part of an intervention trial on diagnostic behaviour of clinicians in a rural district hospital in a low-moderate malaria transmission setting.

Methods

From the beginning of 2005, a randomized controlled trial (RCT) of intermittent preventive treatment for malaria in infants (IPTi) has been conducted at the study hospital. As part of the RCT, the study team offered laboratory quality assurance, and supervision and training of paediatric ward staff using information on malaria epidemiology in the community. Data on clinical and blood slide confirmed cases of malaria from 2001 to 2005 were extracted from the hospital records.

Results

The proportion of blood slides positive for malaria parasites had decreased from 21% in 2001 to 7% in 2005 (p < .01). The proportion of outpatient and inpatient cases diagnosed as malaria ranged between 34% and 28% from 2001 to 2004 and this decreased substantially to 17% after the introduction of the package of training and support in 2005 (p < .01). There was no clear trend in the ratio of blood slide examined versus total diagnosis of malaria.

Conclusion

It may be possible to change the diagnostic behaviour of clinicians by rigorous training using local malaria epidemiology data and supportive supervision.
A Longitudinal Study of the Effects of Word Frequency and Rime-Neighborhood Size on Beginning Readers' Rime Reading Accuracy in Words and Nonwords
Authors: Calhoon J. Anne , Leslie Lauren
Published: December 2006

Beginning readers' rime reading accuracy was assessed over three years to examine the influence of word frequency and rime-neighborhood size (the number of single syllable words with the same rime) on words presented in lists and stories. Twenty-seven 1st- and 2nd- grade students read 54 words and 27 nonwords containing rimes from different size neighborhoods. In Year 1, children showed effects of neighborhood size in high frequency words read in stories and in low frequency words read in lists and stories. In Year 2, rimes from large neighborhoods were read more accurately than rimes from medium and small neighborhoods in high- and low-frequency words. In Year 3, no effects of rime-neighborhood size were found for high-frequency words, but effects on low-frequency words continued. These results support Leslie and Calhoon's (1995) developmental model of the effects of rime-neighborhood size and word frequency as a function of higher levels of word learning.
Dialogic Responsiveness: Toward Synthesis, Complexity, and Holism in Our Reponses to Young Literacy Learners
Authors: Triplett Cheri Foster
Published: December 2006

In this investigation of classroom literacy contexts, the term “dialogic responsiveness” is introduced and utilized in order to provide a holistic framework for synthesizing, researching, and describing the complexities of responsive dialogue. An in-depth perspective was provided via one reading teacher, who exemplified dialogic responsiveness, as she interacted with six focus students during literacy instruction. A breadth of perspectives was provided via four regular classroom teachers as they interacted with four of these focus students during literacy instruction. Findings reveal how these teachers were able to be responsive to the cultural, cognitive, emotional, motivational, and physical needs of young literacy learners. The findings also detail how each teacher's dialogic responsiveness influenced the literacy participation of students. The complexities of these findings are discussed by reviving and extending a metaphor used previously in the literature-the metaphor of weaving. This metaphor is argued to be useful because it provides holistic insight into the complexities of being dialogically responsive to young literacy learners.
Decodable Texts for Beginning Reading Instruction: The Year 2000 Basals
Authors: Hoffman James V. , Sailors Misty , Patterson Elizabeth U.
Published: December 2006

This study focuses on the features of the first grade texts included in basal readers used for beginning reading instruction in Texas during the year 2000 adoption period. The authors investigated the general features of student texts with respect to the instructional design of the text, the accessibility of the text for beginning readers, and the engaging qualities of the texts. The features of these basal readers were then compared to the programs previously adopted in Texas (1987 and 1993 adoption periods). Using a variety of analyses, findings suggest that the mandate by the state of Texas to include more “decodable” texts did in fact, heavily influence the materials presented to beginning readers. In addition, there was an apparent lock of attention to other features that support beginning readers, specifically, predictability and the engaging qualities of the texts. The findings suggest that policy mandates have a direct influence on the content and nature of reading programs placed in the hands of teachers and students.
Appropriate Appropriation: Functionality of Student Arguments and Support Requests during Small-Group Classroom Discussions
Authors: Michael Nussbaum E.
Published: December 2006

The article examines the claim of Anderson et al. (2001) that students engaged in small-group discussions will tend to imitate and appropriate argument stratagems and other discourse behaviors from one another when it is appropriate to do so. In a study involving 67 5th- and 6th-grade students engaged in numerous small-group discussions, some evidence of appropriation was obtained, especially in regards to asking other students for reasons (“support requests”). There were several cases, however, in which students did not appear to use these requests appropriately. These cases are analyzed from the standpoint of both speech act theory and argumentation frames. The analyses indicate that students experienced a conflict between frames associated with traditional, ritualized participant structures and open, collaborative discussions. The danger of teachers and students mixing discourse frames in alternative learning environments is discussed.
Authority, Performance, and Interpretation in Religious Reading: Critical Issues of Intercultural Communication and Multiple Literacies
Authors: Elster Charles A.
Published: December 2006

This paper addresses two critical issues related to language and literacy. The first is the need to better appreciate how literacy practices and values, whether shared, complementary or disparate, mediate intercultural contact, communication, and conflict. The second issue is how to theorize using new models of what literacy is in an age of multiple literacies and increasingly global communication. From a multiple literacies and new genre perspective, readers give meaning to texts in culturally and historical embedded literacy practices. Focusing on the under-researched area of religious literacy practices, I seek to show how the oral performance of texts and their interpretation by textual communities constitute enactments of textual authority. Using the related frameworks of activity, genre, and critical discourse theories, I examine literacy practices in their sociohistorical contexts. Examples of religious reading practices and stances are drawn primarily from Orthodox Jewish reading practices, which recognize unique authority in the words of the Hebrew Bible, and which practice norms of textual interpretation and performance that are unique to that textual community. Religious reading practices highlight the repertoire of reading genres, strategies, and stances that members of modern multicultural societies learn to control. Because multiple reading traditions define communities, personal identities and power relations, it is critical that researchers and policy-makers avoid the danger of imposing one secularist model of reading on all reading activities, or one set of dominant reading stances on all cultural groups.
Instructional Approaches to Improving Students' Writing of Compare-Contrast Essays: An Experimental Study
Authors: Hammann Lynne A. , Stevens Robert J.
Published: December 2006

Students find compare-contrast writing more difficult than other expository formats (Hiebert, Englert, & Brennan, 1983). Difficulties include problems with acquiring source information, with organizing information into compare-contrast format, or both. This study examined instruction in each area: (a) Summarization Skills supporting acquisition of source information, (b) Compare-Contrast Text Structure supporting organization of information, and (c) Summarization Skills and Text Structure for both processes. Students read two descriptive passages and wrote a compare-contrast essay. Students receiving Text Structure instruction had significantly higher scores on compare-contrast Structure but lower ones on Content than did those in the other groups. Students receiving Summarization Skills instruction had significantly lower scores on Structure than did students in the other groups. Explicit instruction in text structure is recommend for compare-contrast writing, including specific strategy instruction to match learning goals and tasks. Further research is recommended about the interaction of content knowledge and writing strategy knowledge, as well as the role of text structure in reading-writing expository text.
Knowledge, Interest, Recall and Navigation: A Look at Hypertext Processing
Authors: Lawless Kimberly A. , Brown Scott W. , Mills Robert , Mayall Hayley J.
Published: December 2006

This study examines how knowledge and interest affect recall of information from a hypertext environment. Participants were 34 undergraduates enrolled at a college of education in a large western university. Results indicate that domain knowledge significantly predicted both structured and unstructured reading recall of a hypertext. In contrast to patterns found within research on traditional reading environments, interest did not significantly affect recall of hypertext information. Differential navigation patterns emerged in conjunction with varying levels of knowledge and may help to explain these results. The results are discussed in terms of current schema theoretic models of reading comprehension.
Perspectives on Struggling English Language Learners: Case Studies of Two Chinese-Canadian Children
Authors: Li Guofang
Published: December 2006

Chinese learners are often stereotyped as high achievers and overlooked in literacy research. This year-long, qualitative study in a combined Grade 4/5 classroom presents the cases of two struggling Chinese-Canadian learners. The study offers a new perspective on struggling learners by revealing a complex, multilayered understanding of these learners from different social members' viewpoints. I provide detailed descriptions of these learners' literacy experiences and dispositions of learning at school and at home, and their teachers' and parents' perspectives on their struggles with English literacy. The findings suggest that several home and school cultural discontinuities and pedagogical influences contributed to the children's difficulty with literacy. The discontinuities included (1) parents' preference for word-by-word decoding versus teachers' preference for semantic connections between pages, (2) parents' and teachers' different interpretations of what and how much homework should be given, (3) parents' and teachers' perspectives on the causes of the children's low literacy performance, and (4) lack of communication between the school and home. The pedagogical influences included (1) decontextualized literacy activities and lack of direct instruction, (2) instructional materials that were detached from the learners' cultural backgrounds, (3) insufficient recognition and utilization of students' resources in their first language, and (4) problematic assessment of these learners. The study raises critical issues in understanding the multivoicedness concerning struggling English language learners and provides educators with guidance for effective instructional planning and for building school-parent partnerships.
The Influence of Accelerated Reader on the Affective Literacy Orientations of Intermediate Grade Students
Authors: Mallette Marla H. , Henk William A. , Melnick Steven A.
Published: December 2006

Although the highly popular Accelerated Reader (AR) book reading incentive program claims to motivate children of all reading ability levels, very little independent empirical research has examined this assertion. To help fill this void, we used two related three-factor mixed designs with Method (AR vs. Control), Gender, and either Grade Level (fourth vs. fifth) or Reading Ability (high vs. low) to explore AR's influence on the reading attitudes and self-perceptions of children in two comparable school districts. The analyses indicate that AR positively influenced academic reading attitudes, but not recreational ones, and that it negatively influenced two types of self-perceptions in low achieving male readers. These findings and others of consequence are discussed along with implications for future research.
Developing and Validating the Classroom Literacy Environmental Profile (CLEP): A Tool for Examining the “Print Richness” of Early Childhood and Elementary Classrooms
Authors: Wolfersberger Mary E. , Reutzel D. Ray , Sudweeks Richard , Fawson Parker C.
Published: December 2006

In this report, the development, field testing, and validation of the Classroom Literacy Environment Profile (CLEP) are described. In the first phase, characteristics of print-rich classroom environments were identified, defined, and organized into categories through a review of the literature, classroom observations, and teacher focus groups. In the second phase of the project, categories and themes interpreted from phase one data were used to write and review the initial items of the instrument. In phase three, generalizability evidence for the CLEP instrument was examined using a G or generaliz-ability study. Classrooms and items evidenced large variance components indicating that the degree of implementation of print-rich classroom environments was reliably discriminated using the CLEP. Following the G study, three D or decision studies were conducted in which the numbers of raters and the number of rating occasions were varied to determine acceptable levels of generalizability and error.
Neuroendocrine Phenotype Analysis in Five Patients with Isolated Hypogonadotropic Hypogonadism due to a L102P Inactivating Mutation of GPR54
Authors: Tenenbaum-Rakover Yardena , Commenges-Ducos Monique , Iovane André , Aumas Chantal , Admoni Osnat , de Roux Nicolas
Published: December 2006

Context: Loss of function of the G protein-coupled receptor of kisspeptins (GPR54) was recently described as a new cause of isolated hypogonadotropic hypogonadism. In vivo studies performed in several species have confirmed the major role of kisspeptins in neuroendocrine regulation of the gonadotropic axis and therefore sexual maturation.

Objective: The objective of this study was to specify the exact contribution of kisspeptins and GPR54 to the initiation of puberty in humans.

Design: Detailed neuroendocrine descriptions were performed in five patients with isolated hypogonadotropic hypogonadism bearing a new GPR54-inactivating mutation.

Results: A homozygous mutation (T305C) leading to a leucine substitution with proline (L102P) was found in the five affected patients. This substitution completely inhibited GPR54 signaling. Phenotypic analysis revealed variable expressivity in the same family, either partial or complete gonadotropic deficiency. LH pulsatility analysis showed peaks with normal frequency but low amplitude. Repeated GnRH tests performed between 12 and 21 yr of age in one affected male revealed progressive changes in pituitary response from an early pubertal to an almost full pubertal pattern. Double GnRH test stimulations performed at a 120-min interval showed reduced dynamic pituitary response in GPR54-mutated patients.

Conclusion: GPR54 inactivation does not impede neuroendocrine onset of puberty; rather, it delays and slows down pubertal maturation of the gonadotropic axis. The L102P loss of function mutation in GPR54 results in a more quantitative than qualitative defect of gonadotropic axis activation.
Sorting of Fas ligand to secretory lysosomes is regulated by mono-ubiquitylation and phosphorylation
Authors: Zuccato Elisabetta , Blott Emma J. , Holt Oliver , Sigismund Sara , Shaw Michael , Bossi Giovanna , Griffiths Gillian M.
Published: December 2006

Fas ligand (FasL), a potent mediator of apoptosis expressed by CTL and NK cells, is sorted into the inner vesicles of secretory lysosomes for release via exosome-like vesicles. Previous studies identified a proline-rich domain in the cytoplasmic tail required for sorting FasL to secretory lysosomes, but the mechanisms by which this occurs have not been identified. Here we demonstrate that the PRD of FasL binds Fgr, Fyn and Lyn tyrosine kinases, leading to phosphorylation of FasL. Loss of phosphorylation reduces internalisation of FasL into multivesicular bodies. FasL is also directly mono-ubiquitylated at lysines flanking the PRD and mutation of these lysines reduces MVB localisation of FasL. Phosphorylation is not required for ubiquitylation because FasL lacking all tyrosines undergoes mono-ubiquitylation. These studies show that phosphorylation and ubiquitin signals regulate the sorting of FasL to secretory lysosomes by controlling entry into multivesicular bodies.
Closed-loop control of start of combustion using difference pressure management
Authors: Lee Kangyoon , Yoon Maru , Son Myeong-hyeon , Sunwoo Myoungho
Published: December 2006

A great deal of attention is being paid to the common-rail direct injection (CRDI) diesel engine as a promising technology for enhancing engine performance and satisfying stringent emission regulations. In a conventional CRDI diesel engine, the start of combustion (SOC) is controlled in an open-loop manner by adjusting the start of energizing (SOE) of an injector. The open-loop SOC control cannot compensate for unexpected variations in the injection delay and ignition delay resulting from cycle-by-cycle variation, cylinder-to-cylinder variation, production variation, and ageing. In this study, cylinder pressure was investigated as a means for controlling the SOC of a CRDI diesel engine. Various pressure variables were compared for the purpose of detecting the SOC of a CRDI diesel engine. The crank angle position at which the difference pressure becomes 10 bar (CADP10) was selected as the pressure variable for the detection of the SOC. The control performance was evaluated with engine-dynamometer experiments in steady and transient operating conditions. The experimental results showed that difference pressure managing can be effectively used for real-time detection of the SOC. Furthermore, the SOC detection technique enables the fuel control strategy to be transformed from an open-loop scheme to a closed-loop scheme.
Experimental durability assessment and life prediction of vehicle suspension components: A case study of steering knuckles
Authors: Zoroufi M , Fatemi A
Published: December 2006

The recent emphasis on more reliable life predictions for fatigue-critical parts in ground vehicles would result in a reduction in costly and time-consuming traditional component testing practices. This paper aims at implementing experimental and predictive durability approaches to vehicle suspension components. Forged steel and cast aluminium steering knuckles were chosen as typical components. The fatigue behaviours of components were investigated via constant-amplitude load-controlled fatigue tests. Finite element models of the knuckles were analysed using linear and non-linear methods. Nominal stress, local stress, and local strain life prediction approaches were employed and compared with experimental results to evaluate the accuracy and validity of these approaches. The strengths and shortcomings of the applied models and the alternative analysis techniques are discussed. It is shown that among the contemporary life prediction procedures used in the automotive industry, the local strain approach in conjunction with the plasticity-corrected simple elastic analysis procedure yields reasonable life predictions that are typical of more complex and much more time-consuming non-linear analysis. A number of complexities such as material property variability, variable-amplitude and multiaxial loadings, manufacturing parameters, and environmental effects on durability assessment are also discussed.
Performance analysis and parametric design of the dual-mode planetary gear hybrid powertrain
Authors: Ahn Kukhyun , Cho Sungtae , Lim Wonsik , Park Yeong-il , Lee Jang Moo
Published: December 2006

The multimode electrically variable transmissions (EVTs) are an advancement of the conventional planetary gear hybrid powertrains (PGHPs). Using the analytical methodologies once applied to the single-mode PGHP, the dual-mode PGHP was investigated. The transmission efficiency and the system optimal operation point maximizing the system overall efficiency were analysed. With the system optimal operation points, the fuel economies of the dual-mode PGHP vehicle were calculated assuming constant-velocity cruising and NEDC mode driving. The top velocity and the acceleration performance were also estimated. To assign appropriate parameters for the new system, the design space and the optimization problem were defined using the vehicle performances from the analyses. An approach with various optimization techniques is proposed, and the optimal parametric design is obtained. The dual-mode PGHP showed improvements in efficiency and dynamic performances compared with the single-mode PGHP. In particular, the powertrain is expected to have advantages because it uses a smaller-sized motor/generator (MG) or two identical machines as two MGs.
Modelling and test results of the Archimedes wave swing
Authors: de Sousa Prado M G , Gardner F , Damen M , Polinder H
Published: December 2006

The objective of this paper is to describe the modelling and some of the offshore test results of the full-scale model of Archimedes wave swing (AWS) at Portugal in 2004. The AWS is a system that converts ocean wave energy into electric energy. A pilot plant of this system has been built. The paper starts with the derivation of a model for the floater motion. Next, the generator system is described and modelled. The generator system consists of a permanent-magnet linear synchronous generator with a current source inverter. Subsequently, test results are presented to validate the models for the floater motion and the generator. Finally, some conclusions are drawn.
A compact equation for the prediction of eddy-induced slip in centrifugal impellers
Authors: von Backström T W
Published: December 2006

The single relative eddy (SRE) method for the prediction of relative-eddy-induced slip in centrifugal impellers proposes the existence of only one slip-inducing eddy in a rotating impeller, compared with the commonly assumed multiple eddies, with one eddy per blade passage. In the SRE method, the eddy-induced slip factor depends on the blade solidity, weighted by an auxiliary coefficient F that is a function of blade angle and blade number. The paper presents a series of increasingly accurate new expressions for F. The best fit leads to a compact equation for slip factor, giving very good agreement (within 0.003) with the numerically calculated slip factors of Busemann for impellers with four or more blades and reasonable agreement (within 0.02) for single-bladed impellers for any blade angle from 0° to 90°.
Adaptive control of coupled-drives apparatus based on polynomial theory
Authors: Kubalčík M , Bobál V
Published: December 2006

Control of a coupled-drives apparatus laboratory model as a two-input-two-output system is presented. Control algorithms based on polynomial theory and pole assignment methods are proposed. Three control algorithms are implemented and compared. Both one-degree-of-freedom and two-degree-of-freedom control system configurations were used. Problems of decoupling, where compensators suppress the interactions between control loops, were also solved. Adaptive algorithms were used to control the model. The recursive least-squares method with directional forgetting was used for the identification process. The results of real-time experiments are also included.
Bond graphs of open systems: A water rocket example
Authors: Redfield R. C.
Published: December 2006

A model of a small-scale water rocket is developed as an example of open-system modelling by both a bond graph approach and a more classical method. In addition to the formulation and bond graph development, a goal of the research is to determine the benefits of the bond graph approach into affording an insight into the system dynamics. Both modelling approaches yield equivalent differential equations, as they should, while the bond graph approach yields significantly more insight into the system dynamics. If a modelling goal is to simply find the system equations and predict behaviour, the classical approach may be more expeditious. If insight and ease of model modification are desired, the bond graph technique is probably the better choice.
Bond-graph-based model simplification for system analysis: Application to a railway traction device
Authors: Gandanegara G , Roboam X , Sareni B , Dauphin-Tanguy G
Published: December 2006

Heterogeneous and multifield systems can be homogeneously modelled using bond graphs. Even if this formalism contributes to making the system analysis easier, simplifying the device modelling as much as possible is also required in order to obtain the ‘just accurate enough model’ with respect to the design objectives. Two simplification methods are investigated in this paper: the model order reduction algorithm (MORA), depending on the energetic transfers in the systems, and the singular perturbation method (SPM), based on element dynamics. Each method is directly applied on bond graphs. To illustrate their application, a railway traction device is considered as an example. The results obtained by both methods are compared and the conditions of use are analysed. Finally, these two processes have proved their efficiency to reduce the computation time and to simplify the system analysis.
Tuning of Electronic Structures of Quasi-One-Dimensional Halogen-Bridged Ni–Pd Mixed-Metal Complexes, [Ni1−xPdx(chxn)2X]X2 (X = Cl, Br) with Strong Electron Correlation
Authors: Yamashita Masahiro , Takaishi Shinya
Published: December 2006

This article describes the tuning of the electronic structures in a series of quasi-one-dimensional halogen-bridged Ni–Pd mixed-metal complexes, [Ni1−xPdx(chxn)2X]X2 (chxn = 1R,2R-diaminocyclohexane; X, Y = Cl or Br). In these compounds, planar [M(chxn)2] units are bridged by halogen ions (X), forming linear chain M–X–M structures. Therefore, their electronic structures are 1D and are composed of hybridization between the dz2 orbitals of the metal ions and pz orbitals of the bridging halogens. In this system, electron-correlation on the Ni sites and electron–phonon interaction on the Pd sites should compete with each other. Their electronic structures have been investigated by means of the single-crystal reflectance, ESR and IR spectroscopies, electrical conductivities, and X-ray diffuse scattering. Moreover, their local electronic structures have been directly observed by scanning tunneling microscopy (STM) using single-crystals at room temperature and under ambient pressure. As a result, while the oxidation state of the Ni sites is +3 in all mixing ratios in these compounds due to strong electron-correlation, the conversion from the PdIII Mott–Hubbard states to the PdII–PdIV mixed-valence states is observed around x ≈ 0.90 for Br and x ≈ 0.85 for Cl. Interestingly, the spin-soliton in Ni0.05Pd0.95(chxn)2Br3 was directly observed by STM for the first time.
Photoinduced Charge-Separation and Charge-Recombination Processes of Oligo(thienyleneethynyl)–Fullerene Dyad Molecules
Authors: Fujitsuka Mamoru , Makinoshima Takashi , Takamizawa Atushi , Araki Yasuyuki , Ito Osamu , Obara Yuko , Aso Yoshio , Otsubo Tetsuo
Published: December 2006

Photoinduced charge-separation and -recombination processes in two series of oligo(thienyleneethynyl)–fullerene dyads (abbreviated as nTE–C60), in which the nTE moiety has a linear (nαTE) or zigzag structure (nβTE), have been investigated by using transient absorption spectroscopy with sub-picosecond laser flash photolysis. Based on the transient absorption spectra, charge separation occurs in nTE–C60 with the rate constants on the order of 1011 s−1, indicating almost quantitative charge separation. For all nTE–C60 dyads, the charge-separation rate-constants in toluene were larger than those in benzonitrile, suggesting that the charge-separation process is a solvent-controlled adiabatic process. On the other hand, the charge-recombination processes going back to the ground state occurred with the rate constants on the order of 108–109 s−1. The charge-recombination rate of nαTE–C60 was faster than that in nβTE–C60 with a zigzag structure, in spite of similar free energy change for the charge recombination.
Geometrical Isomerism and Stability of Mono- and Dichalcogenide Analogs of Carbamic Acid H2NC(=X)YH (X, Y = O, S, Se)
Authors: Kaur Damanjit , Kaur Rupinder Preet , Kaur Pushwinder
Published: December 2006

Activation barriers for geometrical isomerism and tautomerization have been studied for carbamic acid and its mono- and dichalcogenide analogs at B3LYP/6-31+G*, MP2/6-31+G*, and G2MP2 theoretical levels. The studies indicate that carbamic acid with higher chalcogen prefers chalcogen at the chalcogenol position. Proton affinities, gas-phase acidities and atomic charges for these molecules have also been evaluated. Unimolecular, bimolecular, and two-step pathways for the decomposition of carbamic acid and its analogs are also analyzed, from which it was concluded that the two step mechanism is the more plausible pathway.
Effects of Micelles on the Complex Formation of [PtCl(dien)]+ with Biologically Relevant Ligands
Authors: Soldatovic Tanja , Vasic Vesna , Bugarcic Zivadin D
Published: December 2006

Substitution reactions of [PtCl(dien)]+ (dien = diethylenetriamine) with some biologically relevant ligands, such as l-methionine ((l)-Met), glutathione (GSH), and guanosine 5′-monophosphate (5′-GMP), were studied in aqueous 0.10, 0.05, and 0.01 M NaClO4 solutions at pH 2.5 using UV–vis spectrophotometry. The kinetics and mechanism of the complex-formation reactions were studied as a function of nucleophile concentration and temperature. These reactions were also studied in the presence and absence of micelles of sodium dodecyl sulfate (SDS). The presence of anionic micelles accelerated complex-formation. The largest effect of micelles has been observed in the case of l-methionine. On the other hand, an increase in the ionic strength in the presence of micelles caused a decrease in the rate. The negative entropies of activation support an associative complex-formation mechanism.
Exciplex Formation of Intermolecularly Hydrogen-Bonded System between Anthracene and N,N-Dimethylaniline Derivatives
Authors: Ohshiro Ikuma , Ikegami Masashi , Nishimura Yoshinobu , Arai Tatsuo
Published: December 2006

We prepared 2-ureido-4(1H)-pyrimidinone (UPy) derivatives bearing anthracene (AN) and N,N-dimethylaniline (DMA) connected by various lengths (n) of methylene chains (UPyAN, UPyDMAn) to examine the electron-transfer dynamics between the excited state of UPyAN and the ground state of UPyDMAn by spectroscopy. UPyAN and UPyDMAn formed quadruple hydrogen bonds and exhibited exciplex emission between AN and DMA chromophores. From the fluorescence lifetime measurement, the lifetime of exciplex emission increased from 38 to 64 ns with increasing n. The quenching process of singlet excited UPyAN by UPyDMAn is proposed to be different from that of methylene-linked dimethylaniline and anthracene. Furthermore, the results indicate that both AN and DMA keep almost constant distance regardless of n of UPyDMAn. DMA was considered to be located near a quadruple hydrogen-bonding region in the excited state, while deactivation process of exciplex was independent of n, which may be characteristic of a hydrogen-bonded system.
Ruthenium-Catalyzed Addition of Terminal Alkynes to Alkynylstannanes with Migration of the Stannyl Group
Authors: Shirakawa Eiji , Nakayama Kouji , Morita Ryotaro , Tsuchimoto Teruhisa , Kawakami Yusuke , Matsubara Toshiaki
Published: December 2006

In the presence of a catalytic amount of a ruthenium complex coordinated with PBu3, alkynylstannanes (R1C≡CSnBu3) were found to accept the addition of terminal alkynes (R2C≡CH) with a 1,2-shift of the stannyl group to give (E)- and (Z)-1-tributylstannylbut-1-en-3-ynes (Bu3SnC(R1)=CHC≡CR2). Various combinations of substrates having an aromatic and/or aliphatic substituent can be used, and the stereochemical outcome depends largely on the character of these substituents. The reaction of aliphatic terminal alkynes proceeds stereoselectively, and substituent R1 on the alkynylstannanes determines the configuration: E for R1 = alkyl and Z for R1 = aryl. In contrast, the reaction of arylacetylenes gave a mixture of stereoisomers irrespective of the character of substituent R1 on the alkynylstannane. Ruthenium–β-stannylvinylidene complexes generated from a ruthenium complex and an alkynylstannane with migration of the stannyl group are likely to be key intermediates, which accept addition of the C–H bond of terminal alkynes to give the corresponding stannylenynes. DFT calculation clearly shows that the 1,2-shift of the stannyl group on formation of ruthenium–β-stannylvinylidene complexes is more facile than the corresponding 1,2-hydrogen shift of the coordinating terminal alkynes. The effect of the substituents on the stereoselectivity also is discussed based on the calculation.
Synthesis of 4-Aryl-2-sulfenyl-2H-1-benzothiopyran Derivatives by Cyclization of [2-(1-Aryl-2-methoxyvinyl)phenylthio][methyl(or phenyl)thio]methyllithiums
Authors: Kobayashi Kazuhiro , Horiuchi Mai , Miyamoto Kazuna , Morikawa Osamu , Konishi Hisatoshi
Published: December 2006

4-Aryl-2-methyl(or phenyl)thio-2H-1-benzothiopyrans have been prepared in satisfactory yields from the corresponding 1-(1-aryl-2-methoxyethenyl)-2-{[methyl(or phenyl)thiomethyl]thio}benzenes via lithiation of the carbon atom between the two sulfur atoms, followed by intramolecular cyclization with loss of lithium methoxide.
Strategic Investments, Trading, and Pricing Under Forecast Updating
Authors: Chod Jiri , Rudi Nils
Published: December 2006

This paper considers two independent firms that invest in resources such as capacity or inventory based on imperfect market forecasts. As time progresses and new information becomes available, the firms update their forecasts and have the option to trade their resources. The trade contract is determined as the bargaining equilibrium or, alternatively, as the price equilibrium. Assuming a fairly general form of the profit functions, we characterize the Nash equilibrium investment levels, which are first-best under the price equilibrium trade contract, but not under the bargaining equilibrium trade contract. To gain additional insights, we then focus on firms that face stochastic demand functions with constant price elasticity and have contingent pricing power. Assuming a general forecast evolution process, we characterize the impact of the option to trade and the firms’ cooperation on equilibrium investments, expected prices, profits, and consumer surplus. Finally, to study the main driving forces of trading, we employ a well-established and empirically tested forecast updating model in which the forecast evolution process follows a two-dimensional geometric Brownian motion. Under this model, we prove that the equilibrium investments, expected prices, profits, and consumer surplus are nondecreasing in the quality and timing of forecast revisions, in market variability, and in foreign exchange volatility, but are nonincreasing in market correlation.
Production and Inventory Control of a Single Product Assemble-to-Order System with Multiple Customer Classes
Authors: Benjaafar Saif , ElHafsi Mohsen
Published: December 2006

We consider the optimal production and inventory control of an assemble-to-order system with m components, one end-product, and n customer classes. A control policy specifies when to produce each component and, whenever an order is placed, whether or not to satisfy it from on-hand inventory. We formulate the problem as a Markov decision process and characterize the structure of an optimal policy. We show that a base-stock production policy is optimal, but the base-stock level for each component is dynamic and depends on the inventory level of all other components (more specifically, it is nondecreasing). We show that the optimal inventory allocation for each component is a rationing policy with different rationing levels for different demand classes. The rationing levels for each component are dynamic and also nondecreasing in the inventory level of all other components. We compare the performance of the optimal policy to heuristic policies, including the commonly used base-stock policy with fixed base-stock levels, and find them to perform surprisingly well, especially for systems with lost sales.
Impact of Licensing on Investment and Financing of Technology Development
Authors: Kulatilaka Nalin , Lin Lihui
Published: December 2006

Technology innovations continue to be one of the greatest drivers of economic growth. Realizing the value of such innovations, however, requires substantial follow-on investments in development and commercialization. The value of these investments is difficult to capture because of uncertain demand and potential competition. This often leads to difficulties in obtaining outside financing for these investments. In this paper, we explore how licensing contracts can both dissuade other firms from developing alternative technologies and alleviate the financing problem. We develop a model in which a firm that invests in the development efforts of an innovation can license its technology to a potential competitor. A variety of licensing possibilities is considered, including fixed fees, royalty schedules, and two-part licenses consisting of an up-front payment and a capped royalty schedule. When the firm has no financial constraint, a royalty schedule that depends on realized demand dominates a fixed fee per license. When investment funds are constrained, a royalty cap license with an up-front payment can serve as a source of financing. We also study the investment problem conditional on the licensing and financing decisions.
Microstructure of HDTMA+-Modified Montmorillonite and its Influence on Sorption Characteristics
Authors: He Hongping , Zhou Qin , Martens Wayde N. , Kloprogge Theo J. , Yuan Peng , Xi Yunfei , Zhu Jianxi , Frost Ray L.
Published: December 2006

A series of organoclays with monolayers, bilayers, pseudotrilayers, paraffin monolayers and paraffin bilayers were prepared from montmorillonite by ion exchange with hexadecyltrimethylammonium bromide (HDTMAB). The HDTMAB concentrations used for preparing the organoclays were 0.5, 0.7, 1.0, 1.5, 2.0 and 2.5 times the montmorillonite cation exchange capacity (CEC). The microstructural parameters, including the BET-N2 surface area, pore volume, pore size, and surfactant loading and distribution, were determined by X-ray diffraction, N2 adsorption-desorption and high-resolution thermogravimetric analysis (HRTG). The BET-N2 surface area decreased from 55 to 1 m2/g and the pore volume decreased from 0.11 to 0.01 cm3/g as surfactant loading was increased from Na-Mt to 2.5CEC-Mt. The average pore diameter increased from 6.8 to 16.3 nm as surfactant loading was increased. After modifying montmorillonite with HDTMAB, two basic organoclay models were proposed on the basis of HRTG results: (1) the surfactant mainly occupied the clay interlayer space (0.5CEC-Mt, 0.7CEC-Mt, 1.0CEC-Mt); and (2) both the clay interlayer space and external surface (1.5CEC-Mt, 2.0CEC-Mt, 2.5CEC-Mt) were modified by surfactant. In model 1, the sorption mechanism of p-nitrophenol to the organoclay at a relatively low concentration involved both surface adsorption and partitioning, whereas, in model 2 it mainly involved only partitioning. This study demonstrates that the distribution of adsorbed surfactant and the arrangement of adsorbed HDTMA+ within the clay interlayer space control the efficiency and mechanism of sorption by the organoclay rather than BET-N2 surface area, pore volume, and pore diameter.
Influence analysis for the factor analysis model with ranking data
Authors: Xu Liang , Poon Wai‐Yin , Lee Sik‐Yum
Published: December 2006

Influence analysis is an important component of data analysis, and the local influence approach has been widely applied to many statistical models to identify influential observations and assess minor model perturbations since the pioneering work ofCook (1986). The approach is often adopted to develop influence analysis procedures for factor analysis models with ranking data. However, as this well‐known approach is based on the observed data likelihood, which involves multidimensional integrals, directly applying it to develop influence analysis procedures for the factor analysis models with ranking data is difficult. To address this difficulty, a Monte Carlo expectation and maximization algorithm (MCEM) is used to obtain the maximum‐likelihood estimate of the model parameters, and measures for influence analysis on the basis of the conditional expectation of the complete data log likelihood at the E‐step of the MCEM algorithm are then obtained. Very little additional computation is needed to compute the influence measures, because it is possible to make use of the by‐products of the estimation procedure. Influence measures that are based on several typical perturbation schemes are discussed in detail, and the proposed method is illustrated with two real examples and an artificial example.
Strategic defensiveness: Public and private responses to group criticism
Authors: Hornsey Matthew J. , Frederiks Elisha , Smith Joanne R. , Ford Lindsay
Published: December 2006

This paper explores the strategic processes associated with responding to group criticism. In Experiment 1, Australians received criticism of their country from either an in‐group or an out‐group member. When participants believed their evaluations of the criticisms were private, they reported being more defensive when criticized by an out‐group relative to an in‐group member. However, this intergroup sensitivity effect disappeared on some measures when participants were led to believe their evaluations of the criticisms could be seen by an in‐group audience. In Experiment 2, which focused on participants' identity as social science students, the attenuation of the intergroup sensitivity effect emerged only when the in‐group audience was relatively high‐status. Furthermore, in both experiments, increased reports of defensiveness in public only occurred in response to an in‐group critic and not to an out‐group critic. Theoretical and practical implications for intergroup and intragroup communication are discussed.
Inflammasome Components NALP 1 and 3 Show Distinct but Separate Expression Profiles in Human Tissues Suggesting a Site-specific Role in the Inflammatory Response
Authors: Kummer J. Alain , Broekhuizen Roel , Everett Helen , Agostini Laetitia , Kuijk Loes , Martinon Fabio , Bruggen Robin van , Tschopp Jürg
Published: December 2006

Several autoinflammatory disorders such as Muckle-Wells syndrome are characterized by mutations in the NALP3/cryopyrin gene. NALP3 and NALP1 proteins can assemble to inflammasomes that activate caspase-1, resulting in the processing of proinflammatory cytokines IL-1β and IL-18. The present study was designed to determine which cells and tissues express NALP1 and NALP3. Monoclonal antibodies were developed and their use revealed distinct distribution profiles of NALP1 and NALP3. Granulocytes, monocytes (very weakly), dendritic cells, and B and T cells all express NALP1 and NALP3. Highest levels of NALP1 are found in T cells and Langerhans cells. Furthermore, NALP1 is present in glandular epithelial structures such as stomach, gut, lung, and, surprisingly, in neurons and testis. In contrast to NALP1, NALP3 shows a more restricted tissue distribution with expression mainly in non-keratinizing epithelia in the oropharynx, esophagus, and ectocervix. Moreover, NALP3 expression is found in the urothelial layer in the bladder. Likewise, a difference in subcellular distribution between NALP1 and NALP3 is observed because NALP1 is localized mainly in the nucleus, whereas NALP3 is predominantly cytoplasmic. We propose that the presence of NALP3 in epithelial cells lining the oral and genital tracts allows the rapid sensing of invading pathogens, thereby triggering an innate immune response.
Visual Representation: Implications for Decision Making
Authors: Lurie Nicholas H. , Mason Charlotte H.
Published: December 2006

A large number of visualization tools have been created to help decision makers understand increasingly rich databases of product, customer, sales force, and other types of marketing information. This article presents a framework for thinking about how visual representations are likely to affect the decision processes or tasks that marketing managers and consumers commonly face, particularly those that involve the analysis or synthesis of substantial amounts of data. From this framework, the authors derive a set of testable propositions that serve as an agenda for further research. Although visual representations are likely to improve marketing manager efficiency, offer new insights, and increase customer satisfaction and loyalty, they may also bias decisions by focusing attention on a limited set of alternatives, increasing the salience and evaluability of less diagnostic information, and encouraging inaccurate comparisons. Given this, marketing managers are advised to subject insights from visual representations to more formal analysis.