bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of Eukaryotic Initiation Factor 4E by Converging Signaling Pathways during Metabotropic Glutamate Receptor-Dependent Long-Term Depression
Authors: Banko Jessica L. , Hou Lingfei , Poulin Francis , Sonenberg Nahum , Klann Eric
Published: February 2006

Long-term depression (LTD) is an activity-dependent decrease in synaptic efficacy that can be induced in hippocampal area CA1 by pharmacological application of the selective group I metabotropic glutamate receptor (mGluR) agonist 3,5-diyhroxyphenylglycine (DHPG). Recent work has demonstrated that DHPG-induced LTD recruits at least two signal transduction pathways known to couple to translation, the mitogen-activated protein kinase kinase (MEK)–extracellular signal-regulated kinase (ERK) signaling pathway and the phosphoinositide 3-kinase (PI3K)–Akt–mammalian target of rapamycin (mTOR) signaling pathway. However, it remains unclear which translation factors are engaged by these two signaling pathways during mGluR-LTD. In this study, we investigated whether the group I mGluRs couple to the cap-dependent translation proteins: Mnk1, eIF4E, and 4E-BP. We found that both the MEK–ERK and PI3K–mTOR signaling pathways are critical for the DHPG-induced regulation of these translation factors. Furthermore, we demonstrate that increasing eIF4F complex availability via the genetic elimination of 4E-BP2 can enhance the degree of LTD achieved by DHPG application in an ERK-dependent manner. Our results provide direct evidence that cap-dependent translation is engaged during mGluR-LTD and demonstrate that the MEK–ERK and PI3K–mTOR signaling pathways converge to regulate eIF4E activity after induction of DHPG-LTD.
China in 2005: Hu's in Charge
Authors: Saich Tony
Published: February 2006

China's new development strategy seeks to combine populist authoritarianism in the political realm with a shift in economic policy that focuses more on the sustainability and quality of economic growth rather than its speed. Rising social tensions have fed into tightening party control over state and society.
Social Self-Reappraisal Therapy for Social Phobia: Preliminary Findings
Authors: Hofmann Stefan G. , Scepkowski Lisa A.
Published: February 2006

The recent psychopathology literature suggests that individuals with social phobia overestimate social standards and are deficient in setting and attaining social goals, have a negative perception of themselves as social objects, and show heightened self-focused attention when confronted with social threat. They further overestimate the potential cost of a social encounter, experience their anxiety as uncontrollable and visible to others, view their social skills as inadequate, rely on safety behaviors and avoidance strategies to control their anxiety, and engage in post-event rumination. Traditional cognitive-behavioral therapy does not adequately address all of these features of social phobia during treatment. We discuss here an enhanced version of cognitive-behavioral treatment for social phobia, which is expressly designed to address these factors. The results of an uncontrolled pilot study suggest that this new treatment may be more effective than traditional cognitive-behavioral therapy for social phobia.
Changing Interpretation and Judgmental Bias in Social Phobia: A Pilot Study of a Short, Highly Structured Cognitive Treatment
Authors: Voncken Marisol J. , Bögels Susan M.
Published: February 2006

Interpretation and judgmental biases concerning negative evaluation are considered important maintaining factors in social phobia. Cognitive models imply that solely changing these core cognitions reduces social anxiety. Standardizing such an intervention in these core biases may simplify and shorten treatment and therefore increase its accessibility. We present pilot data (n =13) of a short (9 sessions), standardized cognitive therapy developed to intervene directly and solely in interpretation and judgmental biases in social phobia. Described are the design of this therapy and the cognitive techniques. This short therapy was effective in reducing social phobic complaints (effect size of 1.4) and interpretation and judgmental biases. In addition, we have indications that this treatment has high accessibility because of its short duration and standardization.
Cover Picture: Composite Silica Spheres with Magnetic and Luminescent Functionalities (Adv. Funct. Mater. 4/2006)
Authors: Salgueiriño‐Maceira V. , Correa‐Duarte M. A. , Spasova M. , Liz‐Marzán L. M. , Farle M.
Published: February 2006

Photographs of a colloidal dispersion of composite nanoparticles with magnetic and luminescent functionalities are shown (left, in column), which are schematically illustrated in the main image. As reported by Salgueiriño‐Maceira and co‐workers on p. 509, such functionalities are imparted by magnetic and semiconductor nanoparticles within a silica matrix. In the absence of a magnetic field the particles are uniformly dispersed, although they accumulate and can be dragged under the influence of a magnetic field. Their movement can be monitored by their photoluminescence.

A new class of highly fluorescent, photostable, and magnetic core/shell nanoparticles in the submicrometer size range has been synthesized from a modified Stöber method combined with the layer‐by‐layer (LbL) assembly technique. Luminescent magnetic nanoparticles are prepared via two main steps. The first step involves controlled addition of tetraethoxysilane to a dispersion of Fe3O4/γ‐Fe2O3 nanoparticles, which are thereby homogeneously incorporated as cores into monodisperse silica spheres. The second step involves the LbL assembly of polyelectrolytes and luminescent CdTe quantum dots onto the surfaces of the silica‐coated magnetite/maghemite particles, which are finally covered with an outer shell of silica. These spherical particles have a typical diameter of 220 ± 10 nm and a saturation magnetization of 1.34 emu g–1 at room temperature, and exhibit strong excitonic photoluminescence. Nanoparticles with such a core/shell architecture have the added benefit of providing a robust platform (the outer silica shell) for incorporating diverse functionalities into a single nanoparticle.
Inside Front Cover: Perfect Bi4Ti3O12 Single‐Crystal Films via Flux‐Mediated Epitaxy (Adv. Funct. Mater. 4/2006)
Authors: Takahashi R. , Yonezawa Y. , Ohtani M. , Kawasaki M. , Nakajima K. , Chikyow T. , Koinuma H. , Matsumoto Y.
Published: February 2006

Flux‐mediated epitaxy has been developed for ferroelectric Bi4Ti3O12 single‐crystal film growth, as shown on the inside cover. The key point is the selection of an appropriate flux material. A combinatorial high‐throughput screening technique reported by Matsumoto and co‐workers on p. 485 has led to the successful discovery of the novel flux composition, Bi–Cu–O, for Bi4Ti3O12 single‐crystal film growth. This flux‐mediated epitaxy is not limited to oxide epitaxy, but is also widely applicable to various promising materials for the realization of non‐Si‐based electronics, such as nitrides, carbides, and halides.

Excellent crystallinity of material films and atomic control of their surface/interface, sufficient for the realization of their optimal physical properties, are technological premises for modern functional‐device applications. Bi4Ti3O12 and related compounds attract much interest as highly insulating, ferroelectric materials for use in ferroelectric random‐access memories. However, it has been difficult thus far for Bi4Ti3O12 films to satisfy such requirements when formed using vapor‐phase epitaxy, owing to the high volatility of Bi in a vacuum. Here, we demonstrate that flux‐mediated epitaxy is one of the most promising and widely applicable concepts to overcome this inevitable problem. The key point of this process is the appropriate selection of a multi‐component flux system. A combinatorial approach has led to the successful discovery of the novel flux composition of Bi–Cu–O for Bi4Ti3O12 single‐crystal film growth. The perfect single‐crystal nature of the stoichiometric Bi4Ti3O12 film formed has been verified through its giant grain size and electric properties, equivalent to those of bulk single crystals. This demonstration has broad implications, opening up the possibility of preparing stoichiometric single‐crystal oxide films via vapor‐phase epitaxy, even if volatile constituents are required.
Freestanding Nanostructures via Layer‐by‐Layer Assembly
Authors: Jiang C. , Tsukruk V. V.
Published: February 2006

Freestanding flexible nanocomposite structures fabricated by layer‐by‐layer (LbL) assembly are promising candidates for many potential applications, such as in the fields of thermomechanical sensing, controlled release, optical detection, and drug delivery. In this article, we review recent advances in the fabrication and characterization of different types of freestanding LbL structures in air and at air/liquid and liquid/liquid interfaces, including micro‐ and nanocapsules, microcantilevers, freely suspended membranes, encapsulated nanoparticle arrays, and sealed‐cavity arrays. Several recently developed fabrication techniques, such as spin‐assisted coating, dipping, and micropatterning, make the assembly process more efficient and impart novel physical properties to the freestanding films.
Impact of flow regime on polydispersity in tubular RAFT miniemulsion polymerization
Authors: Russum James P. , Jones Christopher W. , Schork F. Joseph
Published: February 2006

The flow characteristics of a miniemulsion in a tubular reactor were assessed using a modified dye tracer approach. Metered nitrogen was introduced producing isolated plug flow. The effects of the flow regime were then related to the polydispersity of polystyrene formed using reversible addition fragmentation chain transfer (RAFT). While nonideal flow was exhibited at very low Reynolds numbers (≤ 20), laminar flow was not. This was attributed to fluid slippage at the wall of the reactor. It was demonstrated that the flow regime and residence time distribution have a direct effect on the molecular weight polydispersity of the polymer. Transient behavior during startup of isolated plug flow was attributed via experimental data and modeling to loss of initiator by way of water droplets left behind by the small cylinders of miniemulsion. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Search in the Web shopping environment
Authors: Mochel Karl
Published: February 2006

The author presents a design case study of a search user interface for Web catalogs in the context of online shopping for consumer products such as clothing, furniture, and sporting goods. The case study provides a review of the user data for the user interface (UI), and the resulting redesign recommendations. Based on the case study and its user data, a set of common user requirements for searching in the context of online shopping is provided.
Evidence‐based practice in search interface design
Authors: Wildemuth Barbara M.
Published: February 2006

An evidence‐based practice approach to search interface design is proposed, with the goal of designing interfaces that adequately support search strategy formulation and reformulation. Relevant findings from studies of information professionals' searching behaviors, end users' searching of bibliographic databases, and search behaviors on the Web are highlighted. Three brief examples are presented to illustrate the ways in which findings from such studies can be used to make decisions about the design of search interfaces. If academic research can be effectively connected with design practice, we can discover which design practices truly are “best practices” and incorporate them into future search interfaces.
Search on mobile phones
Authors: Roto Virpi
Published: February 2006

The search tools familiar from the personal computer are propagating to mobile devices. Are users willing to type keywords with the limited keypad of an ordinary mobile phone? How does mobile search differ from stationary search? The author found that users are surprisingly willing to use search also with the traditional phone keypad, and foresees a search revolution as mobile devices enable location‐based search.
Changing the pace of search: Supporting “background” information seeking
Authors: Jones Matt , Buchanan George , Cheng Tzu‐Chiang , Jain Preeti
Published: February 2006

Almost all Web searches are carried out while the user is sitting at a conventional desktop computer connected to the Internet. Although online, handheld, mobile search offers new possibilities, the fast‐paced, focused style of interaction may not be appropriate for all user search needs. The authors explore an alternative, relaxed style for Web searching that asynchronously combines an offline handheld computer and an online desktop personal computer. They discuss the role and utility of such an approach, present a tool to meet these user needs, and discuss its relation to other systems.
The impact analysis of language differences on an automatic multilingual text summarization system
Authors: Wang Fu Lee , Yang Christopher C.
Published: February 2006

Based on the salient features of the documents, automatic text summarization systems extract the key sentences from source documents. This process supports the users in evaluating the relevance of the extracted documents returned by information retrieval systems. Because of this tool, efficient filtering can be achieved. Indirectly, these systems help to resolve the problem of information overloading. Many automatic text summarization systems have been implemented for use with different languages. It has been established that the grammatical and lexical differences between languages have a significant effect on text processing. However, the impact of the language differences on the automatic text summarization systems has not yet been investigated. The authors provide an impact analysis of language difference on automatic text summarization. It includes the effect on the extraction processes, the scoring mechanisms, the performance, and the matching of the extracted sentences, using the parallel corpus in English and Chinese as the tested object. The analysis results provide a greater understanding of language differences and promote the future development of more advanced text summarization techniques.
User experiments with the Eurovision cross‐language image retrieval system
Authors: Clough Paul , Sanderson Mark
Published: February 2006

In this article the authors present Eurovision, a text‐based system for cross‐language (CL) image retrieval. The system is evaluated by multilingual users for two search tasks with the system configured in English and five other languages. To the authors' knowledge, this is the first published set of user experiments for CL image retrieval. They show that (a) it is possible to create a usable multilingual search engine using little knowledge of any language other than English, (b) categorizing images assists the user's search, and (c) there are differences in the way users search between the proposed search tasks. Based on the two search tasks and user feedback, they describe important aspects of any CL image retrieval system.
Neuroembryopathic effect of trichloroacetic acid in rats exposed during organogenesis
Authors: Singh Royana
Published: February 2006

BACKGROUND: Halogenated hydrocarbons such as trichloroacetic acid (TCA) are among the most common water supply contaminants in the world. This study examines the effect of TCA on the developing brain of the Charles Foster rat. METHODS: Adult pregnant rats were placed in the test group and exposed to various concentration of TCA (i.e., 1000, 1200, 1400, 1600, and 1800 mg/kg body weight [b.w.]) by oral gavage throughout the period of organogenesis from Gestation Day (GD) 6–15 of gestation. Trichloroacetic acid was administered in the form of trichloroacetate, which is reduced to TCA in the body. The control mother rats were administered an equal volume of distilled water. Fetal brains were examined for their external and histological malformation. RESULTS: On GD 19, TCA administration led to an initial increase of brain weight at 1000 mg/kg b.w. and then a weight reduction after TCA doses of 1200 mg/kg b.w. and over. The brain of the formalin‐fixed fetuses at 1000 and 1200 mg/kg b.w. showed hydrocephalus with breech of the ependymal lining, altered choroids plexus architecture, and increased apoptosis. At doses of 1400 mg/kg b.w. and above, the brain showed not only enhanced apoptosis of the neuronal cells, but extravasation of erythrocytes within the cortical parenchyma, vacuolation of the neuropil, and multiple cavity formation. CONCLUSION: With an increase in dose of TCA i.e., 1200 mg/kg b.w. and above, there is enhanced apoptosis, leading to increased neuronal death, which consequently led to the reduction in the brain weight as compared to controls. The fetal central nervous system is susceptible to the toxic effect of TCA. Birth Defects Res (Part B) 2006. © 2006 Wiley‐Liss, Inc.
Developmental toxicity of orally administered technical dimethoate in rats
Authors: Farag Amina T. , Karkour Tarek Abdel‐Zaher , El Okazy Ahmed
Published: February 2006

BACKGROUND: Dimethoate (O,O‐dimethyl‐S‐(N‐methylcarbamoyl‐methyl) phosphorodithioate), an organophosphate insecticide, was examined for its potential to produce developmental toxicity in rats after oral administration. METHODS: Pregnant Fischer 344 rats were given sublethal doses of 0 (corn oil), 7, 15, and 28 mg/kg/day dimethoate by gavage on gestation days (GD) 6–15. Maternal effects in 15 and 28 mg/kg/day dose groups included cholinergic signs such as tremors, diarrhea, weakness, and salivation, and depression in the maternal and fetal brain acetylcholinesterase (AChE) activities. Other maternal toxicity that included reduction in body weight and feed consumption was observed only in the treated group of 28 mg/kg/day. No maternal toxicity was apparent in the 7 mg/kg/day dose group. RESULTS: Maternal exposure to dimethoate during organogenesis significantly affected the number of live fetuses, early resorption, and mean fetal weight in the 28 mg/kg/day dose group. No external, visceral, and skeletal abnormalities were observed in any of the treated groups compared to the control. CONCLUSIONS: On the basis of the present results dimethoate can produce clinical signs of toxicity and significant inhibition of the maternal and fetal AChE activities in dose groups of 15 and 28 mg/kg/day and showed fetotoxicity without teratogenic effects at 28 mg/kg/day. Birth Defects Res (Part B) 77:40–46, 2006. © 2006 Wiley‐Liss, Inc.
Environmental tobacco smoke and sudden infant death syndrome: a review
Authors: Adgent Margaret A.
Published: February 2006

Environmental tobacco smoke (ETS), containing the developmental neurotoxicant, nicotine, is a prevalent component of indoor air pollution. Despite a strong association with active maternal smoking and sudden infant death syndrome (SIDS), information on the risk of SIDS due to prenatal and postnatal ETS exposure is relatively inconsistent. This literature review begins with a discussion and critique of existing epidemiologic data pertaining to ETS and SIDS. It then explores the biologic plausibility of this association, with comparison of the known association between active maternal smoking and SIDS, by examining metabolic and placental transfer issues associated with nicotine, and the biologic responses and mechanisms that may follow exposure to nicotine. Evidence indicates that prenatal and postnatal exposures to nicotine do occur from ETS exposure, but that the level of exposure is often substantially less than levels induced by active maternal smoking. Nicotine also has the capacity to concentrate in the fetus, regardless of exposure source. Experimental animal studies show that various doses of nicotine are capable of affecting a neonate's response to hypoxic conditions, a process thought to be related to SIDS outcomes. Mechanisms contributing to deficient hypoxia response include the ability of nicotine to act as a cholinergic stimulant through nicotinic acetylcholine receptor (nAChR) binding. The need for future research to investigate nicotine exposure and effects from non‐maternal tobacco smoke sources in mid to late gestation is emphasized, along with a need to discourage smoking around both pregnant women and infants.Birth Defects Res. (Part B)77:69–85, 2006. © 2006 Wiley‐Liss, Inc.
Japanese medaka (Oryzias latipes): developmental model for the study of alcohol teratology
Authors: Wang Xueqing , Williams Erin , Haasch Mary L. , Dasmahapatra Asok K.
Published: February 2006

BACKGROUND: Animal models are necessary to investigate the mechanism of alcohol‐induced birth defects. We have used Japanese medaka (Oryzias latipes) as a non‐mammalian model to elucidate the molecular mechanism(s) of ethanol teratogenesis. METHODS: Medaka eggs, within 1 hr post‐fertilization (hpf) were exposed to waterborne ethanol (0–1000 mM) in hatching solution for 48 hr. Embryo development was observed daily until 10 days post‐fertilization (dpf). The concentration of embryonic ethanol was determined enzymatically. Cartilage and bones were stained by Alcian blue and calcein, respectively and skeletal and cardiovascular defects were assessed microscopically. Genetic gender of the embryos was determined by PCR. Levels of two isoenzymes of alcohol dehydrogenase (Adh) mRNAs were determined by semi‐quantitative and real‐time RT‐PCR. RESULTS: The concentration of ethanol required to cause 50% mortality (LC50) in 10 dpf embryos was 568 mM, however, the embryo absorbed only 15–20% of the waterborne ethanol at all ethanol concentrations. The length of the lower jaw and calcification in tail fin cartilaginous structures were reduced by ethanol exposure. Active blood circulation was exhibited at 50+ hpf in embryos treated with 0–100 mM ethanol; active circulation was delayed and blood clots developed in embryos treated with 200–400 mM ethanol. The deleterious effects of ethanol were not gender‐specific. Moreover, ethanol treatment was unable to alter the constitutive expression of either Adh5 or Adh8 mRNA in the medaka embryo. CONCLUSIONS: Preliminary results suggested that embryogenesis in medaka was significantly affected by ethanol exposure. Phenotypic features normally associated with ethanol exposure were similar to that observed in mammalian models of fetal alcohol syndrome. The results further indicated that medaka embryogenesis might be used as an alternative non‐mammalian model for investigating specific alterations in gene expression as a means to understand the molecular mechanism(s) of ethanol‐induced birth defects. Birth Defects Res (Part B) 77:29–39, 2006. © 2006 Wiley‐Liss, Inc.
Antimalarial drugs – host targets (re)visited
Authors: Cunha‐Rodrigues Margarida , Prudêncio Miguel , Mota Maria M. , Haas Werner
Published: February 2006

Every year, forty percent of the world population is at risk of contracting malaria. Hopes for the erradication of this disease during the 20th century were dashed by the ability of Plasmodium falciparum, its most deadly causative agent, to develop resistance to available drugs. Efforts to produce an effective vaccine have so far been unsuccessful, enhancing the need to develop novel antimalarial drugs. In this review, we summarize our knowledge concerning existing antimalarials, mechanisms of drug‐resistance development, the use of drug combination strategies and the quest for novel anti‐plasmodial compounds. We emphasize the potential role of host genes and molecules as novel targets for newly developed drugs. Recent results from our laboratory have shown Hepatocyte Growth Factor/MET signaling to be essential for the establishment of infection in hepatocytes. We discuss the potential use of this pathway in the prophylaxis of malaria infection.
Inhibitors of human indoleamine 2,3‐dioxygenase identified with a target‐based screen in yeast
Authors: Vottero Eduardo , Balgi Aruna , Woods Kate , Tugendreich Stuart , Melese Teri , Andersen Raymond J. , Mauk A. Grant , Roberge Michel
Published: February 2006

Indoleamine 2,3‐dioxygenase (IDO) is a tryptophan degradation enzyme that is emerging as an important drug target. IDO is expressed by many human tumors to help them escape immune detection, and it has been implicated in depression and in the formation of senile nuclear cataracts. There is a need for potent and selective IDO inhibitors for use in research and as lead compounds for drug development. We show that expression of human IDO in a Saccharomyces cerevisiae tryptophan auxotroph restricts yeast growth in the presence of low tryptophan concentrations and that inhibition of IDO activity can restore growth. We use this assay to screen for IDO inhibitors in collections of pure chemicals and crude natural extracts. We identify NSC 401366 (imidodicarbonimidic diamide, N‐methyl‐N"‐9‐phenanthrenyl‐, monohydrochloride) as a potent nonindolic IDO inhibitor (Ki=1.5 ± 0.2 μM) that is competitive with respect to tryptophan. We also use this assay to identify the active compound caulerpin from a crude algal extract. The yeast growth restoration assay is simple and inexpensive. It combines desirable attributes of cell‐ and target‐based screens and is an attractive tool for chemical biology and drug screening.
Ligand‐Template Directed Assembly: An Efficient Approach for the Supramolecular Encapsulation of Transition‐Metal Catalysts
Authors: Kleij Arjan W. , Reek Joost N. H.
Published: February 2006

Supramolecular encapsulation of small guest molecules inside well‐defined cavities of molecular capsules has witnessed broad attention because of the unusual behaviour of these systems. The molecular capsules generally consist of rigid complementary building blocks that are held together by multiple, complementary non‐covalent interactions. Interestingly, it has been shown that chemical transformations can take place inside these capsules and in some examples the reaction is accelerated, while in other cases otherwise instable intermediates could be isolated in the capsulated form. Many reactions of interest require a transition‐metal (TM) catalyst, and the creation of new capsules in which such catalysts are implemented within the structure is thus required for the development of resourceful type of catalyst systems for these processes. In this concept article we will discuss new strategies to arrive at such systems, with a focus on a ligand‐templated approach. In this approach, multifunctional ligands are used as templates for the encapsulation process by supramolecular building blocks and concomitantly for the formation of TM complexes that are active in catalytic processes. The obtained encapsulated transition‐metal catalysts show unusual reactivity and selectivity behaviour that will be discussed in detail.
Slater‐Like Model for Carbon 1s Core Ionization Energies of Halomethanes
Authors: Cao Chenzhong
Published: February 2006

Based on the atomic electron affinity EA, the average energy of the valence‐shell electrons EI and the polarizability α, the charge effect and the relaxation effect were evaluated for the carbon 1s core ionization energies of halomethanes CHnY4−n−mZm (Y, Z=F, Cl, Br, I). The charge effect was scaled by the electronegativity discrepancy (the discrepancy of EA and the discrepancy of EI between the C and H or halogen atom in the CH or Chalogen chemical bond). The relaxation effect (induced dipole) was scaled by the charge on the carbon atom together with the polarizability of the H and halogen atoms. Further, the electrostatic relaxation shielding ΔSi of the carbon 1s electron in the halomethane was expressed by the charge effect together with the relaxation effect. By introducing ΔSi into the Slater model, a Slater‐like model was obtained for calculating the carbon 1s core ionization energy E1,C of halomethane, whose correlation coefficient r is 0.99985 and the average absolute error is only 0.041 eV between the calculated and the experimental carbon 1s core ionization energies for 27 halomethanes. Also the cross‐correlation was tested by the leave‐one‐out (LOO) cross‐validation method, and the obtained model has good predictive ability and stability (the correlation coefficient rcv is 0.99976, the average absolute error between the predicted and the experimental values is only 0.052 eV). The proposed model perhaps lays a good foundation for computing the core ionization energies of various atoms in more complex molecules.
Novel Insights into the Mechanism of the Ortho/Para Spin Conversion of Hydrogen Pairs: Implications for Catalysis and Interstellar Water
Authors: Limbach Hans‐Heinrich , Buntkowsky Gerd , Matthes Jochen , Gründemann Stefan , Pery Tal , Walaszek Bernadeta , Chaudret Bruno
Published: February 2006

The phenomenon of exchange coupling is taken into account in the description of the magnetic nuclear spin conversion between bound ortho‐ and para‐dihydrogen. This conversion occurs without bond breaking, in contrast to the chemical spin conversion. It is shown that the exchange coupling needs to be reduced so that the corresponding exchange barrier can increase and the given magnetic interaction can effectively induce a spin conversion. The implications for related molecules such as water are discussed. For ice, a dipolar magnetic conversion and for liquid water a chemical conversion are predicted to occur within the millisecond timescale. It follows that a separation of water into its spin isomers, as proposed by Tikhonov and Volkov (Science 2002, 296, 2363), is not feasible. Nuclear spin temperatures of water vapor in comets, which are smaller than the gas‐phase equilibrium temperatures, are proposed to be diagnostic for the temperature of the ice or the dust surface from which the water was released.
Nine fluorescence parameter analysis on a four‐color fluorescence activated flow cytometer
Authors: Frischmann Ursula , Müller Werner
Published: February 2006

Background

In many cases a frequent monitoring of blood is important, e.g. during an infection. Often the availability of blood is the limiting factor.

Methods

50 μl blood were stained and analyzed using a standard four‐color cytometer. Percentages of leukocytes were calculated by FlowJo software.

Results

Our protocol allows the differentiation of B cells, T cells, NK cells, neutrophils, and monocytes/macrophages in small volumes of blood.

Conclusions

Using nine fluorochrome‐labeled antibodies and a specific gating strategy we were able to differentiate the main immune cells in minute amounts using one staining step. © 2006 International Society for Analytical Cytology
Analysis and visualization of cell movement in the developing zebrafish brain
Authors: Langenberg Tobias , Dracz Tadeusz , Oates Andrew C. , Heisenberg Carl‐Philip , Brand Michael
Published: February 2006

Detailed reconstruction of the spatiotemporal history of embryonic cells is key to understanding tissue formation processes but is often complicated by the large number of cells involved, particularly so in vertebrates. Through a combination of high‐resolution time‐lapse lineage tracing and antibody staining, we have analyzed the movement of mesencephalic and metencephalic cell populations in the early zebrafish embryo. To facilitate the analysis of our cell tracking data, we have created TracePilot, a software tool that allows interactive manipulation and visualization of tracking data. We demonstrate its utility by showing novel visualizations of cell movement in the developing zebrafish brain. TracePilot (http://www.mpi‐cbg.de/tracepilot) is Java‐based, available free of charge, and has a program structure that allows the incorporation of additional analysis tools. Developmental Dynamics 235:928–933, 2006. © 2006 Wiley‐Liss, Inc.
Asymmetric localization of Numb:EGFP in dividing neuroepithelial cells during neurulation in Danio rerio
Authors: Reugels Alexander M. , Boggetti Barbara , Scheer Nico , Campos‐Ortega José A.
Published: February 2006

In the neural plate and tube of the zebrafish embryo, cells divide with their mitotic spindles oriented parallel to the plane of the neuroepithelium, whilst in the neural keel and rod, the spindle is oriented perpendicular to it. This change is achieved by a 90° rotation of the mitotic spindle. We cloned zebrafish homologues of the gene for the Drosophila cell fate determinant Numb, and analyzed the localization of EGFP fusion proteins in vivo in dividing neuroepithelial cells during neurulation. Whereas Numb isoform 3 and the related protein Numblike are localized in the cytoplasm, Numb isoform 1 is localized to the cell membrane. Time‐lapse analyses showed that Numb 1 is distributed uniformly around the cell cortex in dividing cells during plate and keel stages, but becomes localized at the basolateral membrane of some dividing cells during the transition from neural rod to tube. Using in vitro mutagenesis and Numb:EGFP deletion constructs, we showed that the first 196 amino acids of Numb are sufficient for this localization. Furthermore, we found that an 11–amino acid insertion in the PTB domain is essential for localization to the cortex, whereas amino acids 2–12 mediate the basolateral localization in the neural tube stage. Developmental Dynamics 235:934–948, 2006. © 2006 Wiley‐Liss, Inc.
Vertebrate rel proteins exhibit dorsal‐like activities in early Drosophila embryogenesis
Authors: Prothmann Christian , Armstrong Neil J. , Roth Siegfried , Rupp Ralph A.W.
Published: February 2006

In Drosophila, the Toll/Dorsal pathway triggers the nuclear entry of the Rel protein Dorsal, which controls dorsoventral patterning in early embryogenesis and plays an important role in innate immunity of the adult fly. In vertebrates, the homologous Toll/IL‐1 receptor signaling pathway directs the nuclear localization of Rel/NF‐κB complexes, which activate genes involved in proliferation, apoptosis, and immune response. Recently, first evidence has been reported for the activity of vertebrate Rel proteins and a Toll‐like signaling pathway in the dorsoventral patterning process of Xenopus laevis embryos. Given the evolutionary divergence of the fly and frog model organisms, these findings raise the question, to what extent the effector functions of this pathway have been conserved? Here, we report the ability of two Xenopus Rel proteins to partially substitute for several, but not all, functions of the Dorsal protein in Drosophila embryos. Our results suggest the interaction between Rel proteins and their cytoplasmic inhibitors as an important interface of evolutionary adaptation. Developmental Dynamics 235:949–957, 2006. © 2006 Wiley‐Liss, Inc.
Comparative ontogeny and phylogeny of the upper jaw skeleton in amniotes
Authors: Richman Joy M. , Buchtová Marcela , Boughner Julia C.
Published: February 2006

The morphology, position, and presence of the upper jaw bones vary greatly across amniote taxa. In this review, we compare the development and anatomy of upper jaw bones from the three living amniote groups: reptiles, birds, and mammals. The study of reptiles is particularly important as comparatively little is known about the embryogenesis of the jaw in this group. Our review covers the ontogeny and phylogeny of membranous bones in the face. The aim is to identify conserved embryonic processes that may exist among the three major amniote groups. Finally, we discuss how temporal and spatial regulation of preosseous condensations and ossification centers can lead to variation in the morphology of amniote upper jaw bones. Developmental Dynamics 235:1230–1243, 2006. © 2006 Wiley‐Liss, Inc.
Synthesis and Metallation of the Diphosphanylsilane iPr2Si(PHMe)2
Authors: von Hänisch Carsten , Rubner Oliver
Published: February 2006

The reaction of [LiAl(PHMe)4] with iPr2SiCl2 yields the dialkyldiphosphanylsilane iPr2Si(PHMe)2 (1). This compound is formed as a diastereomeric mixture and was identified by NMR spectroscopy and mass spectrometry. Silane 1 reacts with [Sn{N(SiMe3)2}2] and [Zn{N(SiMe3)2}2] to form the polycyclic compounds [Sn{SnN(SiMe3)2}2{iPr2Si(PMe)2}2] (2) and [{ZnN(SiMe3)2}3{iPr2Si(PMe)2}2H] (3), respectively. The tricyclic compound 2 possesses one Sn–Sn bond and contains tin atoms in the formal oxidation states +1, +2 and +3. The central structural motif of the zinc–phosphorus cluster 3 is a Zn3P4Si2 cage. The compounds [iPr2Si{P(Me)MEt2}2]2 (4: M = Al; 5: M = Ga), which feature an adamantane‐like cage formed by four metal, four phosphorus and two silicon atoms can be obtained by the reaction of 1 with MEt3 (M = Al, Ga). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis and Molecular Structure of [Cp*Ta(Ph)(P6Ph5)]: A Terminal Phosphinidene Complex of the (P6Ph5)3– Ligand (Cp* = C5Me5)
Authors: Wolf Robert , Hey‐Hawkins Evamarie
Published: February 2006

The terminal phosphanyl phosphinidene complex [Cp*Ta(Ph)(P6Ph5)] (2) has been isolated in 16 % yield from the reaction of [Cp*TaCl4] with 2 equiv. Na2(P4Ph4) and displays an η4‐bound (P6Ph5)3– ligand according to X‐ray crystallography and 31P NMR spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A power function model for the basic geometry of solution dolines: considerations from the classical karst of south‐central Slovenia
Authors: Šušteršič France
Published: February 2006

Solution doline geometry is generally too complex to be expressed in terms of a few parameters. A methodology previously designed by the author, based on acquisition of specific field data and subsequent processing by various Fourier techniques, enabled doline geometry to be considered in its entirety. This paper sets out to investigate which simple rotational body (rotated power function) best fits the geometry of 38 dolines studied within the Classical Karst of Slovenia. It transpires that doline radius to depth ratio changes as a function of volume, whereas the mode of change remains stable regardless of the actual dimensions of individual dolines, and is basically the same at different locations. Doline volumes are very close of those of regular cones of the same dimensions, growing relatively deeper as the volume increases. Two poly‐segment models implied by the power function model and based on earlier work are discussed. It transpires that the studied dolines may be relict forms superimposed upon pre‐existing hidden shafts formed by epikarstic water. Copyright © 2006 John Wiley & Sons, Ltd.
Planform dynamics of the Lower Mississippi River
Authors: Harmar Oliver P. , Clifford Nicholas J.
Published: February 2006

This paper presents an analysis of the planform behaviour of the Lower Mississippi River (LMR) using a series of maps and hydrographic surveys covering the period 1765–1975. Data allow analysis at various time and space scales, using fixed and statistically defined reaches, both before and after extensive channel modification. Previous research has interpreted planform change in relation to geomorphological or engineering regime‐type analyses of channel length and width for the LMR as a ‘single system’. The analysis here is broadly consistent with these approaches, but highlights the importance of meander geometry, in the form of the radius of curvature:width ratio. This neglected factor helps resolve paradoxes relating to observed changes in sediment transport and channel stability. When viewed over smaller time and space scales, analysis of dynamics using fixed reach boundaries reveals a downstream trend in the pattern of planform behaviour, which is closely related to the distribution of valley floor deposits, and which also reflects neotectonic influences. Analysis of changes using statistically determined reach boundaries shows that, over shorter time scales, meander trains are continually formed and modified over a period of approximately 120 years. Zones of more‐or‐less dynamic behaviour thus move through the LMR. The research also provides a context for 20th century engineering interventions to the river. These have constrained the magnitude of planform adjustment, but also altered the kind of response that is now possible in relation to changes in discharge and sediment load, and as a consequence of internal feedbacks within the LMR system. Copyright © 2006 John Wiley & Sons, Ltd.
The impact of different gridding methods on catchment geomorphology and soil erosion over long timescales using a landscape evolution model
Authors: Hancock G. R.
Published: February 2006

Many digital elevation models are gridded from irregularly spaced data. This study examines differences in catchment geomorphology and hydrology as a result of kriging and Delaunay triangulation gridding methods. Both methods have been widely used as tools for placing irregularly spaced data onto a regular grid. In the past, numerical modelling has been performed with little assessment of model input variability and the variability produced by different gridding methods has not been fully assessed. Given the importance of the impact of digital elevation model error and potential impact on model output, little work has been done to understand the impact of this type of potential error. Examination of the different catchment realizations demonstrates that when using kriging (point or block) or Delaunay triangulation there are subtle differences in catchment area and elevation as well as networking properties. Subtle differences also exist in hillslope profile. Nevertheless, when comparing catchment descriptors such as the hypsometric curve, area–slope relationship and cumulative area distribution there is little hydrological and geomorphological difference between these catchments. Further, when these digital elevation models are used as landscape input in a long‐term landscape evolution model (i.e. SIBERIA) there is little geomorphological difference or hydrological difference between the two digital elevation models after a 50 000 year modelled period. Consequently either method is appropriate for the study catchment. These findings provide confidence in the conversion of irregularly spaced data onto a regular grid using kriging or Delaunay triangulation and that either method can be used. Copyright © 2006 John Wiley & Sons, Ltd.
Improved association analyses of disease subtypes in case‐parent triads
Authors: Epstein Michael P. , Waldman Irwin D. , Satten Glen A.
Published: February 2006

The sampling of case‐parent triads is an appealing strategy for conducting association analyses of complex diseases. In certain situations, one may have interest in using the triads to identify genetic variants that are associated with a specific subtype of disease, perhaps related to a characteristic cluster of symptoms. A straightforward strategy for conducting such a subtype analysis would be to analyze only those triads with the subtype of interest. While such a strategy is valid, we show that triadswithoutthe subtype of interest can provide additional genetic information that increases power to detect association with the subtype of interest. We incorporate this additional information using a likelihood‐based framework that permits flexible modeling and estimation of allelic effects on disease subtypes and also allows for missing parental data. Using simulated data under a variety of genetic models, we show that our proposed association test consistently outperforms association tests that only analyze triads with the subtype of interest. We also apply our method to a triad study of attention‐deficit hyperactivity disorder and identify a genetic variant in the dopamine transporter gene that is associated with a subtype characterized by extreme levels of both inattentive and hyperactive‐impulsive symptoms.Genet. Epidemiol.2006. © 2006 Wiley‐Liss, Inc.
Genetic association tests based on ranks (GATOR) for quantitative traits with and without censoring
Authors: Allen Andrew S. , Martin Eden R. , Qin Xuejun , Li Yi‐Ju
Published: February 2006

Linkage disequilibrium mapping of quantitative traits is a powerful method for dissecting the genetic etiology of complex phenotypes. Quantitative traits, however, often exhibit characteristics that make their use problematic. For example, the distribution of the trait may be censored, highly skewed, or contaminated with outlying values. We propose here a rank‐based framework for deriving tests of gene and trait association that explicitly take censoring into account and are insensitive to skewness and outlying values. Standard methods for mapping quantitative traits do not take these characteristics into account, which leads to the discarding of valuable information or their improper application. We show how this framework can be applied in nuclear families and discuss its implementation in general pedigrees. The power and efficacy of the approach is illustrated through a series of simulation experiments in which the approach is compared to existing methods. Genet. Epidemiol. 2006. © 2006 Wiley‐Liss, Inc.
Estimation and testing of genotype and haplotype effects in case‐control studies: comparison of weighted regression and multiple imputation procedures
Authors: Cordell Heather J.
Published: February 2006

A popular approach for testing and estimating genotype and haplotype effects associated with a disease outcome is to conduct a population‐based case/control study, in which haplotypes are not directly observed but may be inferred probabilistically from unphased genotype data. A variety of methods exist to analyse the resulting data while accounting for the uncertainty in haplotype assignment, but most focus on the issue of testing the global null hypothesis that no genotype or haplotype effects exist. A more interesting question, once a region of disease association has been identified, is to estimate the relevant genotypic or haplotypic effects and to perform tests of complex null hypotheses such as the hypothesis that some loci, but not others, are associated with disease. Here I examine the assumptions behind, and the performance of, two classes of methods for addressing this question. The first is a weighted regression approach in which posterior probabilities of haplotype assignments are used as weights in a logistic regression analysis, generating a test based on either a weighted pseudo‐likelihood, or a weighted log‐likelihood. The second is a multiple imputation approach using either an improper procedure in which the posterior probabilities are used to generate replicate imputed data sets, or a proper data augmentation procedure. I compare these approaches to a simple expectation substitution (haplotype trend regression) approach. In simulations, all methods gave unbiased parameter estimation but the weighted pseudo‐likelihood, expectation substitution and multiple imputation methods had superior confidence interval coverage. For the weighted pseudo‐likelihood and expectation substitution methods it was necessary to estimate posterior haplotype assignment probabilities using the combined case/control data, whereas for the multiple imputation approaches it was necessary to estimate these probabilities in the case and control groups separately. Overall, multiple imputation was easiest approach to implement in standard statistical software and to extend to more complex models such as those that include gene‐gene or gene‐environment interactions.Genet. Epidemiol.2006. © 2006 Wiley‐Liss, Inc.