bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunomodulation of transgene responses following naked DNA transfer of human factor VIII into hemophilia A mice
Authors: Miao Carol H. , Ye Peiqing , Thompson Arthur R. , Rawlings David J. , Ochs Hans D.
Published: March 2006

A robust humoral immune response against human factor VIII (hFVIII) following naked DNA transfer into immunocompetent hemophilia A mice completely inhibits circulating FVIII activity despite initial high-level hFVIII gene expression. To prevent this undesirable response, we compared transient immunomodulation strategies. Eight groups of mice (n = 4-9 per group) were treated with naked DNA transfer of pBS-HCRHPI-hFVIIIA simultaneously with immunosuppressive reagents that included cyclosporine A (CSA), rapamycin (RAP), mycophenylate mofetil (MMF), a combination of CSA and MMF, a combination of RAP and MMF, a monoclonal antibody against murine CD40 ligand (MR1), recombinant murine Ctla4Ig, and a combination of MR1 and Ctla4Ig. All animals except those receiving only CSA exhibited delayed or absent immune responses against hFVIII. The most effective immunosuppressive regimen, the combination of Ctla4Ig and MR1, prevented inhibitor formation in 8 of 9 animals; the ninth had transient low-titer antibodies. All 9 mice of this group produced persistent, therapeutic levels of hFVIII for more than 6 months. When challenged with the T-dependent antigen bacteriophage Φx174, tolerized mice exhibited normal primary and secondary antibody responses, suggesting that transient immunomodulation to disrupt B/T-cell interaction at the time of plasmid injection effectively promoted long-term immune tolerance specific for hFVIII. (Blood. 2006;108:19-27)
Role of the Undergraduate Student Research Assistant in the New Millennium
Authors: Silva Thais Dutra Nascimento , da Cunha Aguiar Lúcia Cristina , Leta Jaqueline , Santos Dilvani Oliveira , Cardoso Fernanda Serpa , Cabral Lúcio Mendes , Rodrigues Carlos Rangel , Castro Helena Carla
Published: March 2006

In this study, we analyze the contribution of the undergraduate student who participates in the process of generating scientific data and developing a research project using Brazilian research as an example. Historically, undergraduate students have performed the critical role of research assistants in developing countries. This aspect has been underappreciated as a means of generating scientific data in Brazilian research facilities. Brazilian educational institutions are facing major age-related generational changes among the science faculty within the next 5–10 yr. A lack of adequate support for graduate students leads to a concern that undergraduates will not be interested in choosing research assistant programs and, subsequently, academic research careers. To remedy this situation it is important to focus on ways to encourage new research careers and enhance university–industry collaborations.
Computer Simulations Improve University Instructional Laboratories
Authors: Gibbons Nicola J. , Evans Chris , Payne Annette , Shah Kavita , Griffin Darren K.
Published: March 2006

Laboratory classes are commonplace and essential in biology departments but can sometimes be cumbersome, unreliable, and a drain on time and resources. As university intakes increase, pressure on budgets and staff time can often lead to reduction in practical class provision. Frequently, the ability to use laboratory equipment, mix solutions, and manipulate test animals are essential learning outcomes, and “wet” laboratory classes are thus appropriate. In others, however, interpretation and manipulation of the data are the primary learning outcomes, and here, computer-based simulations can provide a cheaper, easier, and less time- and labor-intensive alternative. We report the evaluation of two computer-based simulations of practical exercises: the first in chromosome analysis, the second in bioinformatics. Simulations can provide significant time savings to students (by a factor of four in our first case study) without affecting learning, as measured by performance in assessment. Moreover, under certain circumstances, performance can be improved by the use of simulations (by 7% in our second case study). We concluded that the introduction of these simulations can significantly enhance student learning where consideration of the learning outcomes indicates that it might be appropriate. In addition, they can offer significant benefits to teaching staff.
Students' Studying and Approaches to Learning in Introductory Biology
Authors: Tomanek Debra , Montplaisir Lisa
Published: March 2006

This exploratory study was conducted in an introductory biology course to determine 1) how students used the large lecture environment to create their own learning tasks during studying and 2) whether meaningful learning resulted from the students' efforts. Academic task research from the K-12 education literature and student approaches to learning research from the postsecondary education literature provided the theoretical framework for the mixed methods study. The subject topic was cell division. Findings showed that students 1) valued lectures to develop what they believed to be their own understanding of the topic; 2) deliberately created and engaged in learning tasks for themselves only in preparation for the unit exam; 3) used course resources, cognitive operations, and study strategies that were compatible with surface and strategic, rather than deep, approaches to learning; 4) successfully demonstrated competence in answering familiar test questions aligned with their surface and strategic approaches to studying and learning; and 5) demonstrated limited meaningful understanding of the significance of cell division processes. Implications for introductory biology education are discussed.
An Inquiry into Protein Structure and Genetic Disease: Introducing Undergraduates to Bioinformatics in a Large Introductory Course
Authors: Bednarski April E. , Elgin Sarah C.R. , Pakrasi Himadri B.
Published: March 2006

This inquiry-based lab is designed around genetic diseases with a focus on protein structure and function. To allow students to work on their own investigatory projects, 10 projects on 10 different proteins were developed. Students are grouped in sections of 20 and work in pairs on each of the projects. To begin their investigation, students are given a cDNA sequence that translates into a human protein with a single mutation. Each case results in a genetic disease that has been studied and recorded in the Online Mendelian Inheritance in Man (OMIM) database. Students use bioinformatics tools to investigate their proteins and form a hypothesis for the effect of the mutation on protein function. They are also asked to predict the impact of the mutation on human physiology and present their findings in the form of an oral report. Over five laboratory sessions, students use tools on the National Center for Biotechnology Information (NCBI) Web site (BLAST, LocusLink, OMIM, GenBank, and PubMed) as well as ExPasy, Protein Data Bank, ClustalW, the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, and the structure-viewing program DeepView. Assessment results showed that students gained an understanding of the Web-based databases and tools and enjoyed the investigatory nature of the lab.
Developing Information Fluency in Introductory Biology Students in the Context of an Investigative Laboratory
Authors: Lindquester Gary J. , Burks Romi L. , Jaslow Carolyn R.
Published: March 2006

Students of biology must learn the scientific method for generating information in the field. Concurrently, they should learn how information is reported and accessed. We developed a progressive set of exercises for the undergraduate introductory biology laboratory that combine these objectives. Pre- and postassessments of approximately 100 students suggest that increases occurred, some statistically significant, in the number of students using various library-related resources, in the numbers and confidence level of students using various technologies, and in the numbers and confidence levels of students involved in various activities related to the scientific method. Following this course, students should be better prepared for more advanced and independent study.
Teaching Research Integrity and Bioethics to Science Undergraduates
Authors: Turrens Julio F.
Published: March 2006

Undergraduate students in the Department of Biomedical Sciences at the University of South Alabama, Mobile, are required to take a course entitled“ Issues in Biomedical Sciences,” designed to increase students' awareness about bioethical questions and issues concerning research integrity. This paper describes the main features of this course and summarizes the results of a survey designed to evaluate the students' perceptions about the course. A summary of this study was presented at the 2002 Conference on Research Integrity in Potomac, MD, sponsored by the Office of Research Integrity of the National Institutes of Health.
Successive foraminiferal faunas and inferred palaeoenvironments associated with the postglacial (Holocene) marine transgression, Gulf St Vincent, South Australia
Authors: Cann John H. , Murray-Wallace Colin V. , Riggs Naomi J. , Belperio Antonio P.
Published: March 2006

Gulf St Vincent is one of a pair of elongate, triangular, shallow water embayments into the southern coast of continental Australia. From the southern floor of this embayment, within a shallow basin-like depression where present-day water depth is about 40 m, vibracore SV23 recovered c. 4 m of late Quaternary sediments. The uppermost 1.5 m of this core comprises postglacial (Holocene) marine deposits; six radiocarbon ages for the interval 64-130 cm downcore are all around 10 000 cal. yr BP, while two for 18-24 cm are several thousand years younger. Radiocarbon analysis of an oyster shell at 154 cm yielded a minimum age of c. 37 000 cal. yr BP. Well-preserved benthic foraminifera are abundant in all the recovered sediments. The early phase of Holocene marine sedimentation in Gulf St Vincent was marked by the development of a marginal marine, perhaps lacustrine to estuarine environment, as signified by the presence of oogonia, gypsum crystals and the foraminifera Miliolinella labiosa and Elphidium cf. articulatum. Development of seagrass meadows followed; these were inhabited by Nubecularia lucifuga and Discorbis dimidiatus. As the marine transgression proceeded, the environment remained somewhat restricted, as indicated by Ammonia beccarii, but numbers of this species declined giving way to Massilina milletti as conditions began to resemble those of the modern Gulf St Vincent. Culmination of the transgression provided the conditions necessary for the dominance of Ammobaculites reophaciformis and Flintina triquetra. A. reophaciformis and F triquetra therefore record the final episode of the transgression and transition to the modern, deeper water environment. At several lower horizons they also occur as conspicuous spikes, equivalent to their modern abundance. These spikes, which coincide with equivalent decreased numbers of A. beccarii, are interpreted to represent downward bioturbation of the overlying deeper water sediment.
Rapid climate change during the early Holocene in western Europe and Greenland
Authors: Prasad Sushma , Brauer Achim , Rein Bert , Negendank Jörg F. W.
Published: March 2006

Based on microfacies analyses of seasonally laminated varved sediments from lake Holzmaar, Germany, we report evidence of decadal-to century-scale climate variability during the early Holocene. The shifts in climate are documented in the thickness variations and changes in the composition of the varves in response to subtle shifts in limnological conditions. The close similarity between the Holzmaar varve record and the GRIP oxygen isotope record during 7.4-9.0 calendar (cal.) ka suggests that the high frequency climatic variations in both regions were controlled by the same mechanism. Our more detailed studies covering the central 409-yr period (∼7.846-8.255 cal. ka, encompassing the 8.2 ka event) document for the first time, on a seasonal scale, the changing precipitation regimes in western Europe during these climate shifts. We show (i) that winters were drier and summers shorter and cooler in western Europe during colder periods in Greenland, (ii) in contrast to the present-day climate in the Holzmaar region, summer rains were clearly reduced during the early Holocene, and (iii) the climate not only changed rapidly (< 5 years) but recurring drier events were common during the studied period. In the Holzmaar record, the 8.2 ka event is the most prominent and longest of a series of short-term clirnatic oscillations.
The development of pasture woodland in the southwest Swiss Jura Mountains over 2000 years, based on three adjacent peat profiles
Authors: Sjögren Per
Published: March 2006

The pollen content of three adjacent peat profiles has been analysed to study the development of pasture woodland in the small valley Combe des Amburnex (1300 m a.s.l.). Chronostratigraphy based on lowland pollen assemblages and radiocarbon dates was used to correlate and date the profiles. Forest and mire grazing occurred throughout at least the past two millennia. Before the ninth century the forest consisted of about equal parts of Abies, Fagus and Picea. Thereafter Picea increased and is today strongly dominant in the area, likely an effect of selective browsing. The central part of the valley obtained its modern structure of pastures and forests in the twelfth century, and the pasture woodland in general came into existence during the seventeenth century as an effect of extensive fire activity, possibly charcoal production. In the twentieth century grass and nutrient-demanding species increased relative to other herbs.
The Holocene vegetation history of Lake Erhai, Yunnan province southwestern China: the role of climate and human forcings
Authors: Shen Ji , Jones Richard T. , Yang Xiangdong , Dearing John A. , Wang Sumin
Published: March 2006

A pollen diagram from a 6.62 m sediment sequence in Lake Erhai in northwest Yunnan, China was obtained to examine the roles of climate change and human impact on the development of the Erhai lake-catchment system since 12950 cal. yr BP. The record extends back into the Younger Dryas, where the dominance of Betula and deciduous Quercus points to a relatively cold and wet winter climate. After 11 750 cal. yr BP, a warming climate coupled with enhanced summer monsoon precipitation results in the expansion of Tsuga and evergreen broadleaved trees (Cyclobalanopsis, Lithocarpus and Castanopsis). An increase in evergreen oaks and dry-tolerant species after 10 320 cal. yr BP suggests a greater seasonality in rainfall, reflecting a southward shift in the winter front across the region. This trend of increasing temperatures and seasonality is seen to continue through into the mid-Holocene and the onset of the Holocene optimum. A marked decline in arboreal taxa coupled with increased levels of grass (Poaceae) and other disturbance taxa provides the first evidence for human impact in the catchment at c. 6370 cal. yr BP. This early phase of forest clearance leads to the collapse of the natural altitudinal vegetation gradient that existed in the catchment from the Lateglacial. The subsequent expansion of secondary pine forest suggests that these early clearances were part of a sustained period of shifting agriculture. Archaeological and historical records for the region point to a gradual increase in immigration into the region throughout the late Holocene. The increased pressure on the catchment is reflected in the pollen record by a series of clearance phases, which increase in intensity after 2140 cal. yr BP, linked presumably to intensification of agriculture and early urbanization. This trend continues through the last millennium, before a sharp increase in arboreal pollen at the top of the core reflects a phase of reforestation that took place in the catchment over the last 25 years.
Sudden cardiac death and antipsychotics Part 2: Monitoring and prevention
Authors: Abdelmawla Nasser , Mitchell Alex J.
Published: March 2006

Cardiac safety of antipsychotic drugs continues to be a concern for both typical and atypical antipsychotics. Risk appears greatest in those with pre-existing cardiac disease but many patients may have occult cardiovascular disease. In addition, several drugs appear to increase the likelihood of diabetes and weight gain, which may have an additive adverse effect. On the basis of risk of sudden cardiac death and risk of QTc prolongation we suggest considering antipsychotics in two categories – higher and lower risk. Of most concern is the use of large cumulative doses of antipsychotics that are sometimes given inadvertently by different prescribers. Clinicians need to be aware how to read an ECG, and how to monitor physical parameters and interpret the significance of QTc prolongation in relation to antipsychotic prescribing. We suggest provisional guidance on antipsychotic monitoring in relation to cardiac safety but acknowledge that future studies will help clarify which antipsychotic drugs and which concomitant risk factors are most important for those with and without established cardiac disease.
The new developmental psychiatry
Authors: Berney Tom
Published: March 2006

Psychiatric services for children and adolescents with learning disabilities have been subject to fashion and aspiration rather than pragmatic planning, at different times being claimed by different specialties. As services have atrophied, it has become clear how distinct are the clinical issues that arise in this group; issues that show developmental psychiatry at its starkest with a combination of organic, dynamic and systemic factors that require community teamwork. As services and specialties regroup, this evolving area is likely to continue defining itself, perhaps taking in adults with developmental disorders, to emerge as a new specialty, developmental psychiatry. It remains to be seen where this will sit within the health service.
The Interstellar Conundrum: A Survey of Concepts and Proposed Solutions
Authors: GILSTER PAUL A.
Published: March 2006

Abstract: Once considered intractable, the problem of interstellar flight is slowly yielding to analysis. Although manned missions to the stars are exceedingly improbable in this century, the possibility of interstellar robotic probes should not be ruled out. Recent laboratory work and theoretical analysis suggest several near‐term technologies that could, given the development of an adequate space‐based infrastructure, provide the needed propulsion. Laser‐driven lightsails offer the key advantage of leaving the fuel behind, with the laser beam focused by a large Fresnel lens in the outer Solar System. Perhaps more efficient is the use of a particle beam to boost a spacecraft by interacting with its magnetic sail, the latter a system already under intense scrutiny. Variations on “pellet” propulsion using macroscopic objects continue to surface, their mass converted to energy as they arrive at the departing starship. Interstellar flight will be both difficult and expensive, although it can no longer be considered an impossibility. This paper examines the above concepts and relates them to older ideas, such as the Bussard ramjet, that are currently out of favor. The vibrancy of interstellar flight studies is its syncretism—it was through analysis of the drag problem in fusion ramjet designs that a practical means of decelerating an interstellar probe by deployment of a magnetic sail emerged. The intermingling of such ideas offers the hope of robust hybrid concepts that may make interstellar flight a reality.
MarsSat: Assured Communication with Mars
Authors: GANGALE THOMAS
Published: March 2006

Abstract: The author developed the MarsSat concept during the 1990s. For this task, he designed a class of orbits to solve the problem of communicating with crews on Mars when the planet is in solar conjunction as seen from Earth, a planetary configuration that occurs near the midpoint of a conjunction class mission to Mars. This type of orbit minimizes the distance between Mars and the communications satellite; thus, minimizing the size, weight, and power requirements, while providing a simultaneous line‐of‐sight to both Earth and Mars. The MarsSat orbits are solar orbits that have the same period as Mars, but are inclined a few degrees out of the plane of the Mars orbit and also differ in eccentricity from the orbit of Mars. These differences cause a spacecraft in this orbit to rise North of Mars, then fall behind Mars, then drop South of Mars, and then pull ahead of Mars, by some desired distance in each case—typically about 20 million kilometers—in order to maintain an angular separation of a couple of degrees as seen from a point in the orbit of Earth on the opposite side of the Sun. A satellite in this type of orbit would relay communications between Earth and Mars during the period of up to several weeks, when direct communication is blocked by the Sun. These orbits are far superior for this purpose when compared to stationing a satellite at one of the Sun‐Mars equilateral Lagrangian points, L4 or L5, for two reasons. First, L4 and L5 are 228 million kilometers from Mars, about 10 times the distance of a spacecraft in one of the MarsSat orbits, and by virtue of the inverse‐square law, all other things being equal, the signal strength received at L4 or L5 would be one percent of the signal strength received by a spacecraft in one of the MarsSat orbits. Thus, a relay satellite stationed at L4 or L5 would have to be that much more powerful to receive data at the same rate, with concomitant increases in spacecraft size and weight. Second, a number of Martian Trojan asteroids have been discovered at the Sun‐Mars L4 and L5 points, and there are probably countless smaller objects that have collected in these regions that pose a significant threat to any spacecraft located there.
ExoMars Alternative Escape Trajectories with Soyuz/Fregat
Authors: GIL‐FERNÁNDEZ JESÚS , VAN DAMME CARLOS CORRAL , GRAZIANO MARIELLA , AMATA G B , COGO F , PERINO M A
Published: March 2006

Abstract: The objectives of ExoMars are to inject an orbiter around Mars and to land a rover on the surface to look for possible traces of life. During the first stages of the feasibility analysis, the mass margin of the orbiter was very small for a direct transfer in the Soyuz/Fregat scenario. An analysis of the combined use of lunar swing‐bys and the Sun gravity gradient is performed with WESBOT in order to obtain alternative trajectories for injecting higher mass into Mars transfer. WESBOT is a GMV tool to find WSB transfers to the Moon and to design escape trajectories by performing several swing‐bys with the Moon and the Earth. The weak stability boundary has been successfully used for lunar transfers (Hiten, SMART‐1). For escape trajectories from the Earth, the potential mass gains depend on the escape direction and the departure date to make a series of gravity assists with the help of the Sun gravity gradient to save ΔV. Several strategies are studied depending on the number and order of swing‐bys. The departing conditions (date and orbit) are optimized but the arrival date to Mars is maintained because of mission requirements. For each type of strategy, a systematic search of initial guess trajectories is performed. The initial guess trajectory is made up of patched conics arcs and multiple shooting arcs when necessary. The optimal trajectories for the various scenarios are presented and show different morphologies. An analysis in terms of applicability to the ExoMars mission is included.
A Roadmap for Optimal Control: The Right Way to Commute
Authors: Ross I Michael
Published: March 2006

Abstract: Optimal control theory is the foundation for many problems in astrodynamics. Typical examples are trajectory design and optimization, relative motion control of distributed space systems and attitude steering. Many such problems in astrodynamics are solved by an alternative route of mathematical analysis and deep physical insight, in part because of the perception that an optimal control framework generates hard problems. Although this is indeed true of the Bellman and Pontryagin frameworks, the covector mapping principle provides a neoclassical approach that renders hard problems easy. That is, although the origins of this philosophy can be traced back to Bernoulli and Euler, it is essentially modern as a result of the strong linkage between approximation theory, set‐valued analysis and computing technology. Motivated by the broad success of this approach, mission planners are now conceiving and demanding higher performance from space systems. This has resulted in new set of theoretical and computational problems. Recently, under the leadership of NASA‐GRC, several workshops were held to address some of these problems. This paper outlines the theoretical issues stemming from practical problems in astrodynamics. Emphasis is placed on how it pertains to advanced mission design problems.
Low Energy Trajectories and Chaos: Applications to Astrodynamics and Dynamical Astronomy
Authors: BELBRUNO EDWARD
Published: March 2006

Abstract: In recent years the application of methods of chaos theory to astrodynamics has produced new revolutionary types of low energy trajectories in space with important applications. They have uncovered new routes to the Moon demonstrated by various spacecraft—the Japan Hiten in 1991 and the European SMART‐1 in 2004. These applications have also played an important role in a new theory on the origin of the Moon.
Trajectory Analysis for the Lunar Flyby Rescue of AsiaSat‐3/HGS‐1
Authors: OCAMPO C
Published: March 2006

Abstract: On May 13, 1998, the Hughes Global Services 1 Spacecraft (HGS‐1, originally known as AsiaSat 3) became the first commercial spacecraft to fly by the Moon on a trajectory to reposition it into a useful geosynchronous orbit. This was necessary due to the failure of the last stage of the launch vehicle that left it in a high inclination, eccentric, and unusable orbit. The spacecraft did not have enough propellant to perform the maneuvers required to place it into its intended geostationary orbit via a standard transfer trajectory. However, it did have enough propellant to place it on a trajectory that flew by the Moon twice to finally achieve a useful low inclination geosynchronous orbit. In addition to being the first commercial operation in the vicinity of the Moon, it was the last successful lunar mission of the twentieth century. We discuss of the events leading up to the start of the rescue operation that included contributions from external organizations. We also describe the analytic estimates used to construct the trajectory and provide an overview of the details of the actual mission.
Return Time Dynamics as a Tool for Finding Almost Invariant Sets
Authors: THIERE BIANCA , DELLNITZ MICHAEL
Published: March 2006

Abstract: The primary goal of transport theory is to compute the rate at which parts of the phase space of a given dynamical system move from one region to another. In this paper we present a new approach for the identification of those regions in phase space that are relevant for transport computations. More concretely, we construct a decomposition into almost invariant sets—that is, those sets that represent the main sources and sinks for transport phenomena—using return time dynamics. We illustrate this technique by partitioning a certain Poincaré section in the planar circular restricted three body problem into various sets.
The Cdc14p phosphatase affects late cell-cycle events and morphogenesis inCandida albicans
Authors: Clemente-Blanco Andrés , González-Novo Alberto , Machín Félix , Caballero-Lima David , Aragón Luis , Sánchez Miguel , de Aldana Carlos R. Vázquez , Jiménez Javier , Correa-Bordes Jaime
Published: March 2006

We have characterized the CDC14 gene, which encodes a dual-specificity protein phosphatase in Candida albicans, and demonstrated that its deletion results in defects in cell separation, mitotic exit and morphogenesis. The C. albicans cdc14Δ mutants formed large aggregates of cells that resembled those found in ace2-null strains. In cdc14Δ cells, expression of Ace2p target genes was reduced and Ace2p did not accumulate specifically in daughter nuclei. Taken together, these results imply that Cdc14p is required for the activation and daughter-specific nuclear accumulation of Ace2p. Consistent with a role in cell separation, Cdc14p was targeted to the septum region during the M-G1 transition in yeast-form cells. Interestingly, hypha-inducing signals abolished the translocation of Cdc14p to the division plate, and this regulation depended on the cyclin Hgc1p, since hgc1Δ mutants were able to accumulate Cdc14p in the septum region of the germ tubes. In addition to its role in cytokinesis, Cdc14p regulated mitotic exit, since synchronous cultures of cdc14Δ cells exhibited a severe delay in the destruction of the mitotic cyclin Clb2p. Finally, deletion of CDC14 resulted in decreased invasion of solid agar medium and impaired true hyphal growth.
High 1,3-Asymmetric Induction in Addition of Allylic Tin Reagents to Chiral 3-Substituted 3,4-Dihydroisoquinolines Activated by Acyl Chlorides
Authors: Hatano Bunpei , Haraguchi Yoshikazu , Kozima Sinpei , Yamaguchi Ryohei
Published: March 2006

Nucleophilic addition reactions of allylic tin reagents to chiral 3-substituted 3,4-dihydroisoquinolines activated by acyl chlorides afford anti 1,3-disubstituted 1,2,3,4-tetrahydroisoquinolines stereoselectively through high 1,3-asymmetric induction.
Enshuol, a Novel Squalene-derived Pentacyclic Triterpene Alcohol from a New Species of the Red Algal Genus Laurencia
Authors: Matsuo Yoshihide , Suzuki Minoru , Masuda Michio
Published: March 2006

The structure of a novel brominated triterpenoid, designated enshuol, from the red alga Laurencia omaezakiana Masuda sp. ined. (Enshu-sozo) was elucidated by spectroscopic analysis and chemical reactions of a degradation product.
Callicladol, a Novel Cytotoxic Bromotriterpene Polyether from a Vietnamese Species of the Red Algal Genus Laurencia
Authors: Suzuki Minoru , Matsuo Yoshihide , Takahashi Yoshinori , Masuda Michio
Published: March 2006

Callicladol, a novel brominated metabolite has been isolated from Laurencia calliclada Masuda sp. ined., a Vietnamese species of the red algal genus Laurencia. Its structure was deduced from spectral and chemical evidence.
Synthesis and Structure of Nitridotechnetium(V) Complex of Tetradentate Amine Oxime [TcN(pnao)(H2O)]+
Authors: Kani Yuko , Takayama Tsutomu , Inomata Shinji , Sekine Tsutomu , Kudo Hiroshi
Published: March 2006

Nitridotechnetium complex with a tetradentate amine oxime ligand PnAO (propylene amine oxime; 3,3,9,9-tetramethyl-4,8-diazaundecane-2,10-dione dioxime) was synthesized and its structure was determined by X-ray crystallography.
Isomerization of a Linear Pentamine, 1,4,7,10,13-Pentaazatridecane, to a Branched Form, 4-(Aminoethyl)-1,4,7,10-tetraazadecane, on a Schiff-base Copper Complex Relevant to Multi-copper Enzymes
Authors: Motoda Ken-ichiro , Aiba Mika , Kokubo Chiho , Matsumoto Naohide , Okawa Hisashi
Published: March 2006

The 1:2 Schiff-base of 2,6-diformyl-4-methylphenol and 1,4,7,10,13-pentaazatridecane formed a tetranuclear assembly complex {Cu(II)-Cu2(II,II)-Cu(II)} possessing a dinuclear Cu2 core and two mononuclear Cu auxiliaries. The two-electron reduction of the complex and reoxidation in air resulted in the formation of a dinuclear Cu2(II,II) complex of a macrocycle comprised of 2,6-diformyl-4-methylphenol and branched 4-(2-aminoethyl)-1,4,7,10-tetraazadecane (2:2) instead of the linear pentamine.
A Facile Synthesis of Disiloxanes with Functional Groups
Authors: Mori Atsunori , Hishida Tatsuhiro , Soga Yoshiya , Kawakami Yusuke
Published: March 2006

A facile synthetic method to obtain mono and difunctionalized disiloxanes, which can be used as various monomers for speciality polymers is described. The ring-opening of cyclic siloxanes with functionalized organometallic reagents followed by quenching with a variety of silyl chlorides gives the functionalized disiloxanes in good to excellent yields.
Photochemistry of β-Methoxystyrene in the Presence of Nitroarenes. Unusual Products Formation
Authors: D’Auria Maurizio
Published: March 2006

The irradiation of β-methoxystyrene in the presence of nitroarenes gave un unusual product deriving from dimerization and oxidation of the starting material. In the reaction mixture also an amide was identified.
Alkynyldichlorogalliums are Unstable in Hydrocarbon Solvents Dimerization of Alkynyldichlorogalliums via Carbogallation
Authors: Yamaguchi Masahiko , Hayashi Akio , Hirama Masahiro
Published: March 2006

Alkynyldichlorogalliums dimerize in hydrocarbon solvents via carbogallation giving 1,1-dimetallo-1-buten-3-yne derivatives.
Synthesis of a Tetranuclear Manganese Complex with a Cubane Core at the MnIIMnIIIMnIIMnIII Oxidation Level
Authors: Mikuriya Masahiro , Hashimoto Youichi , Kawamori Asako
Published: March 2006

A novel tetranuclear manganese(II, III, II, III) complex with 2,6-bis[N-(4-imidazolylethyl)iminomethyl]-4-methylphenol (HL), [Mn4(L)2(O)2(CH3COO)2](ClO4)2·2C2H5OH·2H2O, has been synthesized and characterized by X-ray crystallography, infrared and electronic absorption spectroscopies, magnetic suscepitibility measurement, and ESR spectroscopy.
Diels-Alder Reaction of 3-Methylthiofuran and Transformation of the Cycloadducts to Substituted Cyclohexenols
Authors: Yamamoto Ichiro , Narasaka Koichi
Published: March 2006

7-Oxabicyclo[2.2.1]hept-2-ene derivatives are prepared by the Diels-Alder reaction employing 3-methylthiofuran as a diene component. A chiral titanium catalyst promotes the Diels-Alder reaction in good enantioselectivity. The cycloadducts are converted to highly functionalized cyclohexenols by treatment with silyl enol ethers and t-butyldimethylsilyl trifluoromethanesulfonate.
Stereoselective Synthesis of 4,5-Dihydro-1,3-thiazole and 4H-5,6-Dihydro-1,3-thiazine Derivatives
Authors: Yasuda Nobuyuki , Karikomi Michinori , Toda Takashi
Published: March 2006

4-Bromomethyl-4,5-dihydro-1,3-thiazoles and 5-bromo-4H-5,6-dithydro-1,3-thiazines were synthesized by intramolecular cyclization of allylthioimidates by the reaction with N-bromosuccinimide (NBS) or bromine in dichloromethane at room temperature.
Ligand ENDOR Study of the Trigonal Bipyramidal Copper Complexes, [Cu(tren)NH3](ClO4)2 and [Cu(tren)NCS]SCN in the Powder State (tren = tris(2-aminoethyl)amine)
Authors: Ehsan Muhammad Qamrul , Ohba Yasunori , Yamauchi Seigo , Iwaizumi Masamoto
Published: March 2006

The HFC and NQC constants for all the coordinating atoms of the ligand tren, tris(2-aminoethyl)amine, in the trigonal bipyramidal (tbp) copper complexes [Cu(tren)NH3](ClO4)2  1 and [Cu(tren)NCS]SCN 2 have been determined from the angle selected ENDOR study in the powder state. The spin distribution and the metal ligand bonding nature in the copper (tbp) complexes are discussed.
Selective Molecular Recognition of Disaccharides by a Biphenyldiboronic Acid at the Air - Water Interface
Authors: Dusemund Claus , Mikami Masafumi , Shinkai Seiji
Published: March 2006

A biphenyldiboronic acid derivative can be used for molecular recognition of disaccharides at the air-water interface. Disaccharides are detected selectively because of the fixed distance between the boronic acid moieties in the molecule and the organized structure of the monolayer.
Ring-Opening Polymerization of 1,1,2,2-Tetramethyl-1,2-disilacyclopentane via Palladium Complex-Catalyzed Si-Si Bond Metathesis
Authors: Uchimaru Yuko , Tanaka Yoshifumi , Tanaka Masato
Published: March 2006

Ring-opening metathesis polymerization of 1,1,2,2-tetramethyl-1,2-disilacyclopentane was found to proceed in the presence of catalytic amounts of a Pd complex (PdCl2(dppb) or PbCl2(dbpb)) and 1,2-difluoro-1,1,2,2-tetramethyldisilane to effectively give a high molecular weight polymer (Mw > 3 × 105).
Mass Spectroscopic Studies on Ion-Molecule Reactions of CF3+ with Benzene and Toluene at Near-Thermal Energy
Authors: Tsuji Masaharu , Aizawa Masato , Nishimura Yukio
Published: March 2006

Gas-phase ion-molecule reactions of CF3+ with C6H6 and C6H5CH3 have been studied at near-thermal energy by using an ion-beam apparatus. The C7H5F2+(93.4 ± 2.2%) and C6H5+(6.6 ± 2.2%) ions are produced for the reaction with C6H6, while the C8H7F2+(84.3 ± 2.4%), C7H8+(7.8 ± 1.5%), and C7H7+(7.9 ± 2.0%) ions are formed for the reaction with C6H5CH3.
Novel Pentanuclear Iron(III) Complex with 2,6-Bis(salicylideneaminomethyl)-4-methylphenol
Authors: Mikuriya Masahiro , Nakadera Keiichi
Published: March 2006

A pentanuclear iron(III) complex with 2,6-bis(salicylideneaminomethyl)-4-methylphenol (H3L), [Fe5(L)2(O)(OH)2(CH3COO)5(dmf)]·C6H6·2H2O (dmf = dimethylformamide) has been synthesized and characterized by magnetic susceptibilities (5–300 K). The X-ray crystal structure analysis has demonstrated that it consists of pentanuclear units where the Fe5 framework has roughly a rectangular-based pyramidal geometry.
Preparation and Structure of Dichloropalladium(II) Complexes of Sterically Protected Diphosphinidenecyclobutenes and Their Synthetic Application as Homogeneous Catalyst
Authors: Toyota Kozo , Masaki Kazuto , Abe Tetsuya , Yoshifuji Masaaki
Published: March 2006

Sterically protected 3,4-bis[(2,4,6-tri-t-butylphenyl)phosphinidene]cyclobutenes reacted with bis(acetonitrile)dichloropalladium(II) to give the corresponding dichloropalladium complexes and the structure of one of the complexes was confirmed by X-ray crystallography. The complexes were utilized as a homogeneous catalyst in the coupling reaction of trimethylsilylacetylene and 1-bromo-4-nitrobenzene.
Kemp’s Acid Imides as Uphill Transport Carriers for Alkaline Earth Metal Ions
Authors: Hirose Takuji , Baldwin Bruce W , Uchimaru Tadafumi , Tsuzuki Seiji , Uebayashi Masami , Taira Kazunari
Published: March 2006

N-Substituted-1,3,5-trimethylcyclohexane-3,5-imido-1-carboxylic acids efficiently transported CaII and MgII from alkaline earth metal ion mixtures against their concentration gradient through a chloroform liquid membrane.
Photocatalytic Decomposition of Trichlorobenzene Using TiO2 Supported on Nickel-Poly(tetrafluoroethylene) Composite Plate
Authors: Uchida Hiroyuki , Katoh Shinobu , Watanabe Masahiro
Published: March 2006

Using TiO2 photocatalysts supported on nickel-poly(tetrafluoroethylene), Ni-PTFE, composite plate, a rapid and complete degradation of trichlorobenzene in dilute aqueous solution was performed. The Ni-PTFE substrate enhanced the decomposition rate of pollutants, since electrons photogenerated in TiO2 were efficiently consumed in the reduction of dissolved oxygen as a reaction coupled with the oxidative degradation.
Preparation of Various Azulenequinone Derivatives by a Nucleophilic Substitution of 3-Bromoazulenequinone Synthones
Authors: Nozoe Tetsuo , Wakabayashi Hidetsugu , Shindo Kimio , Ishikawa Sumio
Published: March 2006

3-Bromo derivatives of 1,5- and 1,7-azulenequinones easily react with various nucleophiles to give 3-methoxy, phenoxy, p-nitrophenoxy, butylthio, butylamino, p-tolylamino, dimethylamino, 2-hydroxyethylamino, azulenyl, and guaiazulenyl derivatives of the respective azulenequinones almost quantitatively. 3-Bromo-1,5- and -1,7-azulenequinones afford the 2,3-bisbutylthio derivatives under basic conditions.
An NMR Study on Complexation of p-tert-Butylcalix[6]arene Ester Derivatives with Ethylammonium Picrate
Authors: Ahn Sangdoo , Chang Suk-Kyu , Kim Taehoon , Lee Jo Woong
Published: March 2006

Complexation of p-tert-butylcalix[6]arene ester derivatives with ethylammonium ion was investigated via measurement of their proton relaxation times and chemical shifts in CDCl3. The results suggest that the endo-type complexes are formed and the overall rotation of these complexes is more rapid than that of the corresponding free hosts.
Effect of Triamine Ligands (L) on the Acidity of L-Zn-OH2 as a Model Compound of CA and AP
Authors: Fujii Yuki , Itoh Toyofumi , Onodera Kazuhiko , Tada Toshiji
Published: March 2006

The acid dissociation constants of coordinated water of L-Zn-OH2 (L = diethylenetriamine (1),N-(2-aminoethyl)-1,3-propanediamine (2), dipropylenetriamine (3), 1,3,5-triaminocyclohexane (4), and 1,5,9-triazacyclododecane (5)) and the hydrolysis rate constants of diphenyl 4-nitrophenyl phosphate (6) promoted by L-Zn-OH were found to correlate linearly with the enthalpy change (ΔH) for the formation of L-Zn-OH2, which corresponds to the binding energy of Zn-L: the smaller the binding energy is, the stronger the Lewis acidity of zinc ion is and the faster the hydrolysis is.
In Vivo Electron Paramagnetic Resonance Imaging of NO-Bound Iron Complex in a Rat Head
Authors: Yoshimura Tetsuhiko , Fujii Satoshi , Yokoyama Hidekatsu , Kamada Hitoshi
Published: March 2006

Electron paramagnetic resonance (EPR) imaging of NO-bound iron complex in the head of the living rat has been carried out by L-band EPR imaging system. The NO-bound iron complex used as an imaging reagent was a nitrosyl iron complex with N-(dithiocarboxy)sarcosine. Intraperitoneal administration of the imaging reagent to a living rat has provided a clear EPR image derived from the paramagnetic complex in the rat head.
Nucleophilic Substitution Reaction of Optically Pure Chloroselenurane with Active Methylene Compounds. Formation of Optically Pure Selenonium Ylides
Authors: Takahashi Tamiko , Kurose Noriyuki , Kawanami Saburo , Nojiri Atsuko , Arai Yoshitsugu , Koizumi Toru , Shiro Motoo
Published: March 2006

Nucleophilic substitution reaction of (RSe)-chloroselenurane 1 with active methylene compounds proceeded in highly stereoselective manner with retention of configuration to give (SSe)-selenonium ylides 2. (SSe)- and (RSe)-Ylides, 2 and 3, were stereospecifically formed from the reaction of (RSe)- and (SSe)-selenoxides, 4 and 5, with active methylene compounds.
Hydrogen-bonded Charge-Transfer Complex of Ethylenediaminoglyoxime Transition Metal Complex with Tetracyanoquinodimethane
Authors: Itoh Tetsuji , Toyoda Jiro , Tadokoro Makoto , Kitagawa Hiroshi , Mitani Tadaoki , Nakasuji Kazuhiro
Published: March 2006

We prepared the hydrogen-bonded charge-transfer complex containing a transition metal, (ethylenediaminoglyoximato)(ethylenediaminoglyoxime)palladium(II), with TCNQ, which showed a segregated stacking mode of crystal structure and contained H-bonds between the anionic and cationic columns and between the cationic columns. The high electrical conductivity (90 Scm−1) was observed.
Structural Determination and Thin Film Preparation of LiYSiO4 by Sol-Gel Method
Authors: Sato Mineo , Ueda Hirokazu , Kono Yasuhisa
Published: March 2006

LiYSiO4 was synthesized by sol-gel method and its crystal structure was determined by the Rietveld analysis. The structure was found to be an olivine-type structure with orthorhombic Pnma space group. The thin film deposited on an quartz substrate could be prepared by a dip-coating method using sol solutions consisting of lithium i-propoxides, silicon tetraethoxide and yttrium acetate.
Kinetics and Mechanism of Ozone Decomposition on a Manganese Oxide Catalyst
Authors: Dhandapani Balamurugan , Oyama Shigeo Ted
Published: March 2006

The ozone decomposition reaction to molecular oxygen was studied in a flow reactor on a MnO2 / γ-Al2O3 / cordierite catalyst. The rate expression is found to depend on ozone concentration, rO3 = k(O3)0.68, but not on O2 or H2O partial pressure. A reaction sequence based on an ionic type intermediate with superoxide (O2−) or peroxide (O22−) character is proposed to explain the kinetics.
Artificial Cell Wall for Plant Protoplast. Coating of Plasma Membrane with Hydrophobized Polysaccharides
Authors: Guo Ze-jian , Kallus Stefan , Akiyoshi Kazunari , Sunamoto Junzo
Published: March 2006

Protoplasts of Daucus carota were coated by a hydrophobized polysaccharide, such as cholesterol-bearing modified pullulan (CHP) or cholesterol-bearing xyloglucan phosphate (CHXP), that provided an artificial cell wall to the protoplast. The polysaccharide-coating was confirmed directly by a confocal laser microscopy using FITC-labeled polysaccharide derivative. The artificial cell wall certainly increased the viability of the protoplasts even in the presence of cellulase.
Ln(OTf)3- or Sc(OTf)3-Catalyzed Three Components Coupling Reactions between Aldehydes, Amines, and Dienes or Alkenes. Efficient Syntheses of Pyridine and Quinoline Derivatives
Authors: Kobayashi Shu , Ishitani Haruro , Nagayama Satoshi
Published: March 2006

Three components coupling reactions between aldehydes, amines, and dienes or alkenes were catalyzed by lanthanide or scandium triflate to afford pyridine and quinoline derivatives in high yields. The Lewis acid catalysts were stable and kept their activity even in the presence of water and amines.
One-Pot Condensation/Hydrosilylation System for IPN Formation
Authors: Iwahara Takahisa , Kotani Jun , Ando Kiyoshi , Yonezawa Kazuya
Published: March 2006

A one-pot low-molecular model reaction system of condensation (1) and hydrosilylation (2) was proposed and studied for preparation of a silicon-based IPN. To make the both reactions proceed selectively, selection of catalysts and hydrosilanes were of importance. Effects of homogeneity of the system were also considered.
Totally Synthetic Voltage Dependent Ion Channel
Authors: Kobuke Yoshiaki , Ueda Ken , Sokabe Masahiro
Published: March 2006

Phosphate monoester of tetra(butylene 1,4-glycol) monobutyl ether was combined with dioctadecyldimetylammonium cation to make an ion pair. When inserted into planar lipid bilayers, it afforded stable and constant single ion channel currents. The open probabilities varied depending on the applied voltage while keeping the conductance constant, giving rise to a mimic of the voltage dependence.
High Efficient Catalytic Oxidation of Steroidal Olefins by Metalloporphyrin-Reductant-Molecular Oxygen Biomimetic Systems
Authors: Solovieva Anna B , Borovkov Victor V , Lukashova Ekaterina A , Grinenko Galina S
Published: March 2006

Catalytic oxidation of steroidal olefins by metalloporphyrin-reductant-molecular oxygen systems produces stereoselectively corresponding 5-α-hydroxy derivatives with high yields and the manganese complexes show higher efficiency in comparison with the iron complex due to the difference in metal-porphyrin orbital interactions.
A Convenient Synthesis of Methyl 2-[2-(1-Amino)ethenyl-bithiazolyl] thiazoline-4-carboxylate, an Important Skeleton of Cyclothiazomycin
Authors: Shin Chung-gi , Ito Akio , Okumura Kazuo , Nakamura Yutaka
Published: March 2006

The convenient syntheses of a few methyl 2-(1-amino)alkenyl thiazoline-4-carboxylates and methyl 2-[2-(1-amino)ethenyl-bithiazolyl] thiazoline-4-carboxylate have been accomplished. The latter is an important partial skeleton of macrobicyclic peptide antibiotic cyclothiazomycin.
Synthesis and Properties of Poly(methylphenylsilane) Containing Anthracene Units
Authors: Suzuki Hiroshi , Satoh Shin , Kimata Yoshinori , Kuriyama Akira
Published: March 2006

A poly(methylphenylsilane) containing anthracene units in the polymer backbone was synthesized by the Wrutz-type reaction of 9,10-bis(methylpropylchlorosilyl)anthracene and methylphenyldichlorosilane. This polymer exhibited light blue photoluminescence with 87% quantum efficiency. The excitation spectrum suggested that energy transfer occurred intramolecularly from the polysilane chain to anthracene in the excited state.
Catalytic Decomposition of N2O over Rhodium-Loaded Metal Oxides
Authors: Oi Junko , Obuchi Akira , Ogata Atsushi , Yagita Hiroshi , Bamwenda Gratian R , Mizuno Koichi
Published: March 2006

The catalytic decomposition of dinitrogen oxide to nitrogen and oxygen was studied over various rhodium-loaded metal oxides. Rh/ZnO was found to have the highest activity. The effects of metal loading and calcination conditions upon the catalytic performance were also examined. An air-pretreated 0.5 wt% Rh/ZnO was found to be the most active catalyst with a reaction rate of 4.0 × 104 μmol (N2O) · g−1 · h−1 under conditions of 950 ppm of N2O and 5% of O2 at 300 °C.