bluuebunny/crossref_metadata_2025 huggingface dataset:
Trends in Aggregate Concentration in the United States
Authors: White Lawrence J
Published: January 2003

I assemble two rarely used data sets to measure aggregate concentration in the U.S. in the 1980s and 1990s. Despite the merger waves of those decades, aggregate concentration declined in the 1980s and the early 1990s, but rose modestly in the late 1990s. The levels at the end of the decade were at or below the levels of the late 1980s or early 1990s. The average size of firm and the relative importance of larger size classes of firms increased, however. Gini coefficients for employment and payroll shares of companies showed moderate but steady increases from 1988 through 1999.
A cross-comparison of retrospective notes extraction and combined notes extraction and patient interview in the completion of a comorbidity index (ACE-27) in a cohort of United Kingdom patients with head and neck cancer
Authors: Paleri V. , Wight R. G.
Published: January 2003

Co-existent comorbidity is a major determinant of treatment outcome in head and neck cancer. Most of the work pertaining to this topic has been done in the United States, where the standard practice is for trained cancer registrars to grade comorbidity using validated indexes by retrospective notes review. The adult comorbidity evaluation – 27 index (ACE-27) is a validated instrument that has been widely used in head and neck cancer. Although the required clinical data may be available in the notes, a significant amount of historical information is required to grade comorbidity. The aim of this study was to assess the accuracy and inter-rater reliability of the retrospective notes review process, in a typical setting in the United Kingdom (UK), by comparing the information obtained on notes review alone by a physician to that available after a structured patient interview. The study concludes that the retrospective notes review is an accurate and reliable technique for grading comorbidity whose completeness can be improved by the use of patient questionnaire as part of a structured interview.
Scala vestibuli cochlear implantation in patients with partially ossified cochleas
Authors: Berrettini Stefano , Forli Francesca , Neri Emanuele , Segnini Giovanni , Franceschini Stefano Sellari
Published: January 2003

Partial cochlear obstruction is a relatively common finding in candidates for cochlear implants and frequently involves the inferior segment of the scala tympani in the basal turn of the cochlea. In such patients, the scala vestibuli is often patent and offers an alternative site for implantation. The current report describes two patients with such partial obstruction of the inferior segment of the basal cochlear turn, caused in one case by systemic vasculitis (Takayasu’s disease) and in the other by obliterative otosclerosis. A scala vestibuli implantation allowed for complete insertion of the electrode array. No problems were encountered during the surgical procedures and the good post-operative hearing and communicative outcomes achieved were similar to those reported in patients without cochlear ossification.

The importance of accurate pre-operative radiological study of the inner ear is underscored, to disclose the presence and define the features of the cochlear ossification and ultimately to properly plan the surgical approach.
Osteochondroma of the posterior nasal septum managed by endoscopic transnasal transseptal approach
Authors: Unlu H. Halis , Unlu Zeliha , Ayhan Semin , Egrilmez Murat
Published: January 2003

A case of osteochondroma of the posterior nasal septum is presented. A 57-year-old female patient presented with a history of bilateral nasal obstruction for 20 years. To the best of our knowledge, this is the second reported case of an osteochondroma of the nasal septum. It was treated by endoscopic transnasal transseptal surgery.
Investigating how individuals conceptually and physically structure file folders for electronic bookmarks: The example of the financial services industry
Authors: Gottlieb Lisa , Dilevko Juris
Published: January 2003

Personal preferences in the development of categorical folders for bookmarks are examined in terms of both the choice and definition of folder domain and the overall structure of the folder system. Study participants from the financial industry were asked to organize the same set of finance‐related bookmarks from a given list, as opposed to describing their organizational approaches using their own personal bookmarks, so that the organizational systems could be compared across the sample. The selection of folder domain is influenced by contextual factors such as intended use and relevancy to current projects. Similarly, the structure of the overall folder system was determined in part by participants' navigational preferences. While the majority of participants created folders that cover the topics of finance, government, accounting, news, law, and tax, the actual definition of these folders and the criteria for inclusion vary across the sample. Furthermore, these criteria cannot be readily discerned from the folder system itself. Variation in folder domain and definition could adversely affect the utility of bookmark management systems for multiple users that involve some degree of standardization. The same variation in interpretation of seemingly identical folders suggests that systems with automatic categorization would not provide users with enough flexibility in how they could organize and access their bookmarks.
GeoSearcher: Location‐based ranking of search engine results
Authors: Watters Carolyn , Amoudi Ghada
Published: January 2003

Many web queries have geospatial dimensions. While online shopping is built on the premise that distance and location are irrelevant (with the possible exception of shipping charges), tourism and onsite inspection of goods have a geospatial dimension and distance and location are relevant factors. Current search engines build indices based on keyword occurrence and frequency for query negotiation using these indices. This approach is fast, robust, and generic but when queries are related to physical locations and distances rather than cyberdistances this approach leaves the user to sort through pages of results. In this paper, we describe an algorithm that assigns location coordinates dynamically to web sites based on the URL. A prototype search system was built using this algorithm that uses this information to re‐rank the results of search engines for queries with a geospatial dimension. We found that over 80% of the URLs tested could be assigned correct location coordinates. This work makes a contribution to retrieval on the web by providing an alternative ranking order for search engine results so that users with queries with a geospatial dimension can more readily use the results of general search engines rather than special purpose applications.
Cell‐Type‐Specific adhesion onto polymer surfaces from mixed cell populations
Authors: Quirk Robin A. , Kellam Barrie , Bhandari Rena N. , Davies Martyn C. , Tendler Saul J. B. , Shakesheff Kevin M.
Published: January 2003

The targeted adhesion of a specific cell type from a mixed cell suspension via the surface presentation of a cell‐specific ligand is demonstrated. This generic strategy is illustrated by the covalent attachment of a galactose derivative to a polylysine backbone via the amine functionality. Following adsorption of the resultant material to a polymer surface, hepatocyte adhesion is increased via the interaction between galactose and asialoglycoprotein receptors in a concentration‐dependent manner. The selective nature of the material is demonstrated by the approximate doubling in the adhesion of hepatocytes relative to a nontargeted cell type (hepatic stellate cells), and an inability of the modified polymer surface to attract additional numbers of the nontargeted cells. This strategy provides a mechanism for controlling the ratios of cell types adhering to scaffold supports, thus enabling the rapid creation of defined coculture systems from heterogeneous cell suspensions. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 625–628, 2003.
Pattern identification and classification in gene expression data using an autoassociative neural network model
Authors: Bicciato Silvio , Pandin Mario , Didonè Giuseppe , Di Bello Carlo
Published: January 2003

The application of DNA microarray technology for analysis of gene expression creates enormous opportunities to accelerate the pace in understanding living systems and identification of target genes and pathways for drug development and therapeutic intervention. Parallel monitoring of the expression profiles of thousands of genes seems particularly promising for a deeper understanding of cancer biology and the identification of molecular signatures supporting the histological classification schemes of neoplastic specimens. However, the increasing volume of data generated by microarray experiments poses the challenge of developing equally efficient methods and analysis procedures to extract, interpret, and upgrade the information content of these databases. Herein, a computational procedure for pattern identification, feature extraction, and classification of gene expression data through the analysis of an autoassociative neural network model is described. The identified patterns and features contain critical information about gene–phenotype relationships observed during changes in cell physiology. They represent a rational and dimensionally reduced base for understanding the basic biology of the onset of diseases, defining targets of therapeutic intervention, and developing diagnostic tools for the identification and classification of pathological states. The proposed method has been tested on two different microarray datasets—Golub's analysis of acute human leukemia [Golub et al. (1999) Science 286:531–537], and the human colon adenocarcinoma study presented by Alon et al. [1999; Proc Natl Acad Sci USA 97:10101–10106]. The analysis of the neural network internal structure allows the identification of specific phenotype markers and the extraction of peculiar associations among genes and physiological states. At the same time, the neural network outputs provide assignment to multiple classes, such as different pathological conditions or tissue samples, for previously unseen instances. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 594–606, 2003.
Weak polymer–electrolyte interaction revealed by Fermi resonance perturbed Raman bands
Authors: Ostrovskii Denis , Edvardsson Magnus , Jacobsson Per
Published: January 2003

A detailed analysis of isotropic and anisotropic Raman spectra of carbonyl stretching vibrations of ethylene carbonate in different systems was conducted. The variation of Fermi resonance perturbed spectral profiles was used to investigate changes in local molecular surroundings in polymer gel–electrolyte systems as a function of their composition. In poly(methyl methacrylate)‐based gels it is found that the matrix interacts very weakly with the solvent molecules, ethylene and propylene carbonates, mostly playing a role of a hydrogen bond‐breaking agent. In gel systems containing lithium salt, however, a new type of coordination appears. Along with the solvent–solvent and solvent–cation couplings characteristic of liquid electrolytes, the spectra of gels demonstrate the presence of mixed states in which cations, solvent molecules and polymer segments take part. The importance of the mixed states for ionic conduction is discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Transmethylation of 2‐(methylthio)benzothiazole on silver sols: a SERS investigation
Authors: Pergolese Barbara , Bigotto Adriano
Published: January 2003

Discrepancies between the SERS and the normal Raman spectra of 2‐(methylthio)benzothiazole (MTBT) led to an extension of the SERS study to include an investigation of the reactivity of this molecule on a silver surface. Experimental evidence indicates a surface reaction of MTBT on silver sol. In particular, it undergoes an intramolecular transmethylation, rearranging to 3‐methylbenzothiazoline‐2‐thione. Experimental data suggest that this transmethylation takes place only because of the presence of the silver surface, which acts as a catalyst. In contrast, the hypothesis of a reaction photo‐induced by the silver surface seems very unlikely. 3‐Methylbenzothiazoline‐2‐thione adsorbs on the silver surface via the lone pairs of the exocyclic sulphur atom and, to some extent, also via the π‐system of the benzene ring. The molecular orientation is inclined with respect to the metal surface. Copyright © 2002 John Wiley & Sons, Ltd.
Raman spectroscopy of synthetic erythrite, partially dehydrated erythrite and hydrothermally synthesized dehydrated erythrite
Authors: Martens Wayde , Frost Ray L. , Kloprogge J. Theo
Published: January 2003

The Raman spectra of the mono, di and octa (commonly known as the mineral erythrite) hydrates of cobalt(II) arsenate synthesized using hydrothermal techniques were obtained. The hydrates can be distinguished by their water hydroxyl stretching bands. Splitting of the AsO stretching vibrations is observed in the 77 K spectrum. The band at 852 cm−1 is assigned to the ν1 symmetric stretching vibration and the band at 790 cm−1 to the ν3 antisymmetric stretching vibration. The low‐wavenumber region was used to identify bands attributable to the ν4 and ν2 modes. Copyright © 2002 John Wiley & Sons, Ltd.
Evaluation of gum exudates from three selected plant species from Tanzania for food and pharmaceutical applications
Authors: Mbuna Julius J , Mhinzi Gaspar S
Published: January 2003

Authenticated gum samples from three plant species from Tanzania were analysed and their potential for food, pharmaceutical and other applications was determined by comparing their physicochemical properties with those of commercial Acacia gums from Tanzania, gum karaya and the specifications demanded by the international regulatory bodies for gum arabic for food and pharmaceutical applications. The gum exudate from Dichrostachys cinerea meets some specifications (moisture content, solubility, insoluble matter and ash) demanded for the identity and purity of gum arabic as stipulated by the international regulatory bodies. The aqueous solution of the gum possesses solubility and viscosity similar to commercial gum arabic. Similarly, the properties of Sterculia quinqueloba gum meet a number of the specifications demanded for gum karaya, except that it contains high levels of tannin which would limit its usefulness in food and pharmaceutical applications. The properties of the gum exudate from Acacia pseudofistula, on the other hand, are different from those of Tanzanian commercial Acacia gums.

© 2002 Society of Chemical Industry
Modeling and simulation of mixed traffic on a prioritized shared medium
Authors: J. Evans Jeffrey , Hood Cynthia S.
Published: January 2003

Network access systems (NAS) such as digital loop carriers (DLC) are increasingly utilizing a shared medium, such as Hybrid Fiber Coax (HFC) to provide point‐to‐multi‐point access from the public switched telephone network (PSTN) to the end user (consumer). New services, such as direct access to the packet switched network (PSN, WWW) have been added to DLC equipment in such a way as to provide for a prioritized set of services over a shared medium in an effort to take advantage of otherwise unused bandwidth. The introduction of such services requires the modeling and analysis of these network access systems. This becomes complex when considering the variability in different service type traffic characteristics. This work identifies a traffic engineering problem of prioritized circuit switched and packet switched (PSTN/PSN) traffic over the same shared medium as it may relate to “perceived” quality of service (QoS). Copyright © 2002 John Wiley & Sons, Ltd.
Trunking of TDM and narrowband services over IP Networks
Authors: Aweya James
Published: January 2003

The recent interest in IP as the vehicle for transporting TDM and narrowband services stems from the possibility of using a common transport network for voice, video, and data, and the flexibility with which new services can be introduced. A key step in the evolution of networks towards a ‘broadband’ IP‐based environment is the ‘graceful’ interworking of the IP networks with the existing networks and services, particularly with the circuit switched telephone network. A ‘graceful’ interworking approach is one whose complexity is minimal and preserves the user's perceived quality of service (QoS). To interwork with a circuit switched network whose services are pre‐dominantly time‐sensitive, the IP network must essentially behave as a transparent ‘link’ in the end‐to‐end connection. This paper presents an overview of the main technical problems to be addressed when trunking TDM and narrowband services over IP networks. Copyright © 2002 John Wiley & Sons, Ltd.
Friendship networks and social, school and psychological adjustment in Chinese junior high school students
Authors: Liu Mowei , Chen Xinyin
Published: January 2003

The purpose of the study was to examine friendship networks and their associations with social, academic and psychological adjustment in Chinese high school students. A sample of 296 eighth grade students, aged 14 years, in two junior high schools in Shanghai, P. R. China, participated in this study. Information on social functioning, social preference, leadership, school‐related competence and problems, academic achievement, and psychological adjustment including loneliness and perceived competence was obtained from multiple sources. By using a computer‐based network analysis program, NEGOPY, friendship groups, liaisons, dyads and isolates were identified. It was found that children who belonged to friendship groups differed from those who had only one or two mutual friends and those who were completely isolated on indexes of social, emotional and school adjustment. Compared with dyads who had mutual friends, group members had higher scores on social and school competence and lower scores on learning problems and loneliness, suggesting that friendship networks might represent a phenomenon distinct from dyadic relationships. Finally, children who had behavioral and academic problems had difficulties not only in getting involved in group networks but also in establishing mutual friendships in the class. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 5–17, 2003.
Beyond parents and peers: The role of important non‐parental adults (VIPs) in adolescent development in China and the United States
Authors: Chen Chuansheng , Greenberger Ellen , Farruggia Susan , Bush Kevin , Dong Qi
Published: January 2003

To understand cross‐cultural differences and similarities in the social contexts for adolescent development, 201 American and 502 Chinese 11th graders were surveyed about a non‐parental adult who had played an important role in their lives (VIPs). Results showed that, compared to adolescents' VIPs in the United States, their Chinese counterparts were more likely to be teachers, to provide support in education‐related areas, and to be considered role models. Chinese VIPs were also reported to exhibit fewer problem behaviors and depressive symptoms and express a higher level of sanctions against adolescent problem behaviors than American VIPs. Adolescents in both cultures reported that their VIPs' positive qualities surpassed those of parents and peers. VIPs' characteristics (e.g., sanctions, problem behavior, warmth, and depressed mood) were significantly associated with adolescent outcomes. These results suggest that although there are cross‐cultural differences in the nature of VIPs, VIPs are a very important part of social context for adolescent development in both the United States and China. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 35–50, 2003.
Learning and motivation of Chinese students in Hong Kong: A longitudinal study of contextual influences on students' achievement orientation and performance
Authors: Salili Farideh , Lai Man Kin
Published: January 2003

The purpose of this study was to investigate the effects of medium of instruction and ability grouping (banding) of schools on students' learning and achievement orientation. A total of 1,807 male and female seventh graders studying in different school bands, using either English or Chinese as a medium of instruction (EMI and CMI respectively) participated in this study over a period of 3 years. They were administered measures of self‐regulated learning strategies, goal orientation, general self‐efficacy, anxiety in learning history as well as measures of self‐efficacy, attitude, and motivation in learning English. The results showed that students studying in upper band schools (i.e., low‐ability schools) used fewer strategies in learning, had lower self‐efficacy, higher surface goal and lower attainment scores than those in lower band schools. In addition, they had less positive attitude, lower levels of motivation and were more anxious in learning English and history than their counterparts in lower bands. The results also showed that CMI students made more use of learning strategies than EMI students. All students, regardless of school types or gender, rated higher on performance goal than any other goals in all 3 years. These findings and others were interpreted in terms of sociocultural values and context of learning in Hong Kong. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 51–70, 2003.
Two ZBP1 KH domains facilitate β-actin mRNA localization, granule formation, and cytoskeletal attachment
Authors: Farina Kim L. , Hüttelmaier Stefan , Musunuru Kiran , Darnell Robert , Singer Robert H.
Published: January 2003

Chicken embryo fibroblasts (CEFs) localize β-actin mRNA to their lamellae, a process important for the maintenance of cell polarity and motility. The localization of β-actin mRNA requires a cis localization element (zipcode) and involves zipcode binding protein 1 (ZBP1), a protein that specifically binds to the zipcode. Both localize to the lamellipodia of polarized CEFs. ZBP1 and its homologues contain two NH2-terminal RNA recognition motifs (RRMs) and four COOH-terminal hnRNP K homology (KH) domains. By using ZBP1 truncations fused to GFP in conjunction with in situ hybridization analysis, we have determined that KH domains three and four were responsible for granule formation and cytoskeletal association. When the NH2 terminus was deleted, granules formed by the KH domains alone did not accumulate at the leading edge, suggesting a role for the NH2 terminus in targeting transport granules to their destination. RNA binding studies were used to show that the third and fourth KH domains, not the RRM domains, bind the zipcode of β-actin mRNA. Overexpression of the four KH domains or certain subsets of these domains delocalized β-actin mRNA in CEFs and inhibited fibroblast motility, demonstrating the importance of ZBP1 function in both β-actin mRNA localization and cell motility.
Dynamic changes in the mobility of LAT in aggregated lipid rafts upon T cell activation
Authors: Tanimura Natsuko , Nagafuku Masakazu , Minaki Yasuko , Umeda Yukio , Hayashi Fumie , Sakakura Junko , Kato Akiko , Liddicoat Douglas R. , Ogata Masato , Hamaoka Toshiyuki , Kosugi Atsushi
Published: January 2003

Lipid rafts are known to aggregate in response to various stimuli. By way of raft aggregation after stimulation, signaling molecules in rafts accumulate and interact so that the signal received at a given membrane receptor is amplified efficiently from the site of aggregation. To elucidate the process of lipid raft aggregation during T cell activation, we analyzed the dynamic changes of a raft-associated protein, linker for activation of T cells (LAT), on T cell receptor stimulation using LAT fused to GFP (LAT-GFP). When transfectants expressing LAT-GFP were stimulated with anti-CD3–coated beads, LAT-GFP aggregated and formed patches at the area of bead contact. Photobleaching experiments using live cells revealed that LAT-GFP in patches was markedly less mobile than that in nonpatched regions. The decreased mobility in patches was dependent on raft organization supported by membrane cholesterol and signaling molecule binding sites, especially the phospholipase Cγ1 binding site in the cytoplasmic domain of LAT. Thus, although LAT normally moves rapidly at the plasma membrane, it loses its mobility and becomes stably associated with aggregated rafts to ensure organized and sustained signal transduction required for T cell activation.
Amyloidogenic processing of the Alzheimer β-amyloid precursor protein depends on lipid rafts
Authors: Ehehalt Robert , Keller Patrick , Haass Christian , Thiele Christoph , Simons Kai
Published: January 2003

Formation of senile plaques containing the β-amyloid peptide (Aβ) derived from the amyloid precursor protein (APP) is an invariant feature of Alzheimer's disease (AD). APP is cleaved either by β-secretase or by α-secretase to initiate amyloidogenic (release of Aβ) or nonamyloidogenic processing of APP, respectively. A key to understanding AD is to unravel how access of these enzymes to APP is regulated. Here, we demonstrate that lipid rafts are critically involved in regulating Aβ generation. Reducing cholesterol levels in N2a cells decreased Aβ production. APP and the β-site APP cleavage enzyme (BACE1) could be induced to copatch at the plasma membrane upon cross-linking with antibodies and to segregate away from nonraft markers. Antibody cross-linking dramatically increased production of Aβ in a cholesterol-dependent manner. Aβ generation was dependent on endocytosis and was reduced after expression of the dynamin mutant K44A and the Rab5 GTPase-activating protein, RN-tre. This inhibition could be overcome by antibody cross-linking. These observations suggest the existence of two APP pools. Although APP inside raft clusters seems to be cleaved by β-secretase, APP outside rafts undergoes cleavage by α-secretase. Thus, access of α- and β-secretase to APP, and therefore Aβ generation, may be determined by dynamic interactions of APP with lipid rafts.
Roles of Gβγ in membrane recruitment and activation of p110γ/p101 phosphoinositide 3-kinase γ
Authors: Brock Carsten , Schaefer Michael , Reusch H. Peter , Czupalla Cornelia , Michalke Manuela , Spicher Karsten , Schultz Günter , Nürnberg Bernd
Published: January 2003

Receptor-regulated class I phosphoinositide 3-kinases (PI3K) phosphorylate the membrane lipid phosphatidylinositol (PtdIns)-4,5-P2 to PtdIns-3,4,5-P3. This, in turn, recruits and activates cytosolic effectors with PtdIns-3,4,5-P3–binding pleckstrin homology (PH) domains, thereby controlling important cellular functions such as proliferation, survival, or chemotaxis. The class IB p110γ/p101 PI3Kγ is activated by Gβγ on stimulation of G protein–coupled receptors. It is currently unknown whether in living cells Gβγ acts as a membrane anchor or an allosteric activator of PI3Kγ, and which role its noncatalytic p101 subunit plays in its activation by Gβγ. Using GFP-tagged PI3Kγ subunits expressed in HEK cells, we show that Gβγ recruits the enzyme from the cytosol to the membrane by interaction with its p101 subunit. Accordingly, p101 was found to be required for G protein–mediated activation of PI3Kγ in living cells, as assessed by use of GFP-tagged PtdIns-3,4,5-P3–binding PH domains. Furthermore, membrane-targeted p110γ displayed basal enzymatic activity, but was further stimulated by Gβγ, even in the absence of p101. Therefore, we conclude that in vivo, Gβγ activates PI3Kγ by a mechanism assigning specific roles for both PI3Kγ subunits, i.e., membrane recruitment is mediated via the noncatalytic p101 subunit, and direct stimulation of Gβγ with p110γ contributes to activation of PI3Kγ.
A Crucial Role of Glycoprotein VI for Platelet Recruitment to the Injured Arterial Wall In Vivo
Authors: Massberg Steffen , Gawaz Meinrad , Grüner Sabine , Schulte Valerie , Konrad Ildiko , Zohlnhöfer Dietlind , Heinzmann Ulrich , Nieswandt Bernhard
Published: January 2003

Platelet adhesion and aggregation at sites of vascular injury is crucial for hemostasis but may lead to arterial occlusion in the setting of atherosclerosis and precipitate diseases such as myocardial infarction. A current hypothesis suggests that platelet glycoprotein (GP) Ib interaction with von Willebrand factor recruits flowing platelets to the injured vessel wall, where subendothelial fibrillar collagens support their firm adhesion and activation. However, so far this hypothesis has not been tested in vivo. Here, we demonstrate by intravital fluorescence microscopy of the mouse carotid artery that inhibition or absence of the major platelet collagen receptor, GPVI, abolishes platelet–vessel wall interactions after endothelial denudation. Unexpectedly, inhibition of GPVI by the monoclonal antibody JAQ1 reduced platelet tethering to the subendothelium by ∼89%. In addition, stable arrest and aggregation of platelets was virtually abolished under these conditions. Using different models of arterial injury, the strict requirement for GPVI in these processes was confirmed in GPVI-deficient mice, where platelets also failed to adhere and aggregate on the damaged vessel wall. These findings reveal an unexpected role of GPVI in the initiation of platelet attachment at sites of vascular injury and unequivocally identify platelet–collagen interactions (via GPVI) as the major determinant of arterial thrombus formation.
Positive Selection of Anti–Thy-1 Autoreactive B-1 Cells and Natural Serum Autoantibody Production Independent from Bone Marrow B Cell Development
Authors: Hayakawa Kyoko , Asano Masanao , Shinton Susan A. , Gui Ming , Wen Li-Jun , Dashoff Joni , Hardy Richard R.
Published: January 2003

A natural serum autoantibody specific for the Thy-1 glycoprotein (anti–Thy-1 autoantibody [ATA]) is produced by B-1 cells that are positively selected by self-antigen. Here, using ATAμκ transgenic mice we show that cells with this B cell receptor are negatively selected during bone marrow (BM) development. In a Thy-1 null environment, BM ATA B cells progress to a normal follicular stage in spleen. However, in a self-antigen–positive environment, development is arrested at an immature stage in the spleen, concomitant with induction of CD5. Such cells are tolerant and short-lived, different from B-1. Nonetheless, ATA-positive selection was evident by self-antigen–dependent high serum ATA production, comprising ∼90% of serum immunoglobulin M in ATAμκ mice. Splenectomy did not eliminate ATA production and transfer of tolerant splenic B cells did not induce it. These findings demonstrate that B-1 positive selection, resulting in the production of natural serum ATA, arises independently from the major pathway of BM B cell development and selection.
DC-SIGN Is the Major Mycobacterium tuberculosis Receptor on Human Dendritic Cells
Authors: Tailleux Ludovic , Schwartz Olivier , Herrmann Jean-Louis , Pivert Elisabeth , Jackson Mary , Amara Ali , Legres Luc , Dreher Donatus , Nicod Laurent P. , Gluckman Jean Claude , Lagrange Philippe H. , Gicquel Brigitte , Neyrolles Olivier
Published: January 2003

Early interactions between lung dendritic cells (LDCs) and Mycobacterium tuberculosis, the etiological agent of tuberculosis, are thought to be critical for mounting a protective anti-mycobacterial immune response and for determining the outcome of infection. However, these interactions are poorly understood, at least at the molecular level. Here we show that M. tuberculosis enters human monocyte-derived DCs after binding to the recently identified lectin DC-specific intercellular adhesion molecule-3 grabbing nonintegrin (DC-SIGN). By contrast, complement receptor (CR)3 and mannose receptor (MR), which are the main M. tuberculosis receptors on macrophages (Mϕs), appeared to play a minor role, if any, in mycobacterial binding to DCs. The mycobacteria-specific lipoglycan lipoarabinomannan (LAM) was identified as a key ligand of DC-SIGN. Freshly isolated human LDCs were found to express DC-SIGN, and M. tuberculosis–derived material was detected in CD14−HLA-DR+DC-SIGN+ cells in lymph nodes (LNs) from patients with tuberculosis. Thus, as for human immunodeficiency virus (HIV), which is captured by the same receptor, DC-SIGN–mediated entry of M. tuberculosis in DCs in vivo is likely to influence bacterial persistence and host immunity.
THE INTERSECTION OF SPHERES IN A SPHERE AND A NEW GEOMETRIC MEANING OF THE ARF INVARIANT
Authors: OGASA EIJI
Published: January 2003

Let [Formula: see text] be a 3-sphere embedded in the 5-sphere S5 (i = 1,2). Let [Formula: see text] and [Formula: see text] intersect transversely. Then the intersection [Formula: see text] is a disjoint collection of circles. Thus we obtain a pair of 1-links, C in [Formula: see text], and a pair of 3-knots, [Formula: see text] in S5 (i = 1, 2). Conversely let (L1, L2) be a pair of 1-links and (X1, X2) be a pair of 3-knots. It is natural to ask whether the pair of 1-links (L1, L2) is obtained as the intersection of the 3-knots X1 and X2 as above. We give a complete answer to this question. Our answer gives a new geometric meaning of the Arf invariant of 1-links.

Let f : S3 → S5 be a smooth transverse immersion such that the self-intersection C consists of double points. Suppose that C is a single circle in S5. Then f-1(C) in S3 is a 1-knot or a 2-component 1-link. There is a similar realization problem. We give a complete answer to this question.
The Kauffman Polynomials of Generalized Hopf Links
Authors: Lu Bin , Zhong Jianyuan K.
Published: January 2003

Following the recent work by Chan [1] and Morton and Hadji [2] on the Homflypt polynomials of some generalized Hopf links, we investigate the polynomials of generalized Hopf links. By studying the Kauffman skein module of the solid torus S1 × D2, we establish a similar skein map on the Kauffman skein module of S1 × D2 which has distinct eigenvalues. Furthermore we are able to calculate the Kauffman polynomials of some specific generalized Hopf links.
DISCRETE KNOTS
Authors: BRIBIESCA ERNESTO
Published: January 2003

A method for representing knots by means of a chain code is presented. Knots which are digitalized and represented by the orthogonal direction change chain code are called discrete knots. Discrete knots are composed of constant straight-line segments using only orthogonal directions. The chain elements represent the orthogonal direction changes of the constant straight-line segments of the discrete knot. There are only five possible orthogonal direction changes for representing any discrete knot. Thus, this chain code only considers relatives directions changes, which allows us to have a unique knot descriptor invariant under translation and rotation. Also, this knot descriptor may be starting point normalized. Finally, this unique knot descriptor produces a numerical string of finite length over a finite alphabet, allows us the usage of grammatical techniques for discrete-knot analysis. Thus, we present some prime discrete knot detection examples within composite discrete knots.
REINHABITING RELIGION: GREEN SISTERS, ECOLOGICAL RENEWAL, AND THE BIOGEOGRAPHY OF RELIGIOUS LANDSCAPE
Authors: Taylor Sarah McFarland
Published: January 2003

This article explores the growing movement of environmentally activist Roman Catholic women religious in North America and the implications of this movement for theorizing new directions in religion and culture. Sisters' creative efforts to conserve traditional religious and cultural forms while opening up these forms to "greener" (ecologically-minded) interpretations reveals the very protean process of religious meaning-making. It also subsequently challenges more static and conventional theoretical models of religion. In particular, the author documents and analyzes the intertwining of bioregional philosophies of "reinhabitation," expressions of American Catholic religious life, and manifestations of "green culture." Integrating geographic, ethnographic, and historical methodologies, the author argues that when researchers approach the study of religion as "biogeographers," they discover complex levels of religious understanding and expression that are otherwise overlooked. Significantly, it is these frequently-missed dimensions of the religious landscape that more accurately reflect the "living and lived" quality of religion.
THE VARIETIES OF NATURE EXPERIENCE
Authors: Griffiths Joanna
Published: January 2003

This paper focuses on the assertion of the Norwegian philosopher Arne Naess (1989: 20) that "ethics follow from how we experience the world." I discuss what the statement might mean when applied to Naessian Deep Ecology. There follows a discussion of the close cohesion between experience and practice in Naessian thought. I attend to Naess's descriptions of the relationship between mystical nature experience and "ecological enlightenment," in which he suggests that an intense union with nature will lead the experiencing individual to enact Deep Ecological thought, as Naess formulates it. I seek to amplify the definition of mystical nature experience with reference to William James's The Varieties of Religious Experience, and particularly to James's assertions about the effects of religious experience on individual action. Naess (1986: 225-239) has cited James's work as a significant influence on his understanding of the terms "self" and "experience." Is Naess advocating a need to reeducate people to experience nature, in the hope that environmental awareness will increase accordingly? What experience of nature would inspire an environmental ethic? I conclude by arguing that Naess's reformative agenda stands in a complex relationship to the emphasis on individual, mystical nature experience as the catalyst to "ecological enlightenment." This complexity has not been satisfactorily resolved within Naessian Deep Ecology.
CHILDREN AND TREES IN NORTH INDIA
Authors: Gold Ann Grodzins
Published: January 2003

Rural children in Rajasthan, North India, express their connections with trees through storytelling and other artistic media, as well as recognizing trees' multiple uses in everyday life. In both imaginative and pragmatic views, trees are seen as vulnerable and requiring protection, but also as shelters for all creatures and bounteous givers of many blessings. Children's perceptions of trees and nature are shaped by local history in which narratives of deforestation are integral to political changes. Current government initiatives to promote environmental awareness and ecological regeneration also influence young people, who take these lessons to heart.
Differential effects of cortical neurotrophic factors on development of lateral geniculate nucleus and superior colliculus neurons: anterograde and retrograde actions
Authors: Wahle Petra , Di Cristo Graziella , Schwerdtfeger Gudrun , Engelhardt Maren , Berardi Nicoletta , Maffei Lamberto
Published: January 2003

Neurotrophins strongly affect visual system development and plasticity. However, the mode of delivery and targets of neurotrophin action are still under debate. For instance, cortical NT-4/5 (neurotrophin 4/5; Ntf4/5) was shown to rescue lateral geniculate nucleus (LGN) neurons from monocular deprivation-induced atrophy suggesting a retrograde action on thalamic afferents. It is still unclear whether LGN neurons respond to NT-4/5 and other neurotrophins during development in animals with normal vision. We now show that infusions of NT-4/5 and NGF (nerve growth factor) into visual cortex at the onset and the peak of the critical period accelerated LGN neuron growth. BDNF (brain-derived neurotrophic factor) was ineffective. The effects of neurotrophin on LGN development were clearly dissociated from the effects at cortical level because soma growth of cortical layer IV and VI neurons was strongly promoted by BDNF. NT-4/5 was only effective at the onset, but no longer at the peak of the critical period suggesting a switch in neurotrophin dependency for these cortical cell classes. To dissociate retrograde and anterograde effects of the TrkB ligands, we analyzed the stratum griseum superficiale (SGS) of the superior colliculus, a target of visual cortical efferents. Indeed, TrkB-expressing inhibitory SGS neurons responded to cortical NT-4/5 infusion with somatic growth. Strikingly, the TrkB-expressing excitatory tectothalamic calbindin neurons in the SGS did not respond. This demonstrated for the first time a selective cell type-specific anterograde action of NT-4/5 and suggested for the LGN that anterograde as well as retrograde effects contribute to soma size regulation. Strikingly, cortical infusion of the cytokine LIF, which affects development of visual cortex neurochemical architecture, transiently inhibited growth of neurons in LGN,cortical layer IV and VI and SGS. In summary, the study presents three important results. First, central neurons regulate soma size development in an age-and ligand-specific fashion. Second, NT-4/5 and NGF accelerate LGN development in rats with normal vision while LIF delays growth. Third,anterogradely transported NT-4/5 effectively promotes neuronal maturation. These differential actions on subcortical neurons may contribute to the different effects of neurotrophins on visual system development and plasticity.
The role ofGrg4in tectal laminar formation
Authors: Sugiyama Sayaka , Nakamura Harukazu
Published: January 2003

Mature chick optic tecta consist of 16 laminae and receive retinal fiber projections in a precise retinotopic manner. Retinal axons arborize in laminae a-f of the SGFS, but do not cross the border between lamina f and g. In order to elucidate molecular mechanisms of tectal laminar formation, we first looked at the migration of tectal postmitotic cells. We found that the migration pattern of postmitotic cells changes around E5 and that late migratory cells intervened laminae that were formed by early migratory cells. The coincident appearance of Grg4 expression in the tectal ventricular layer and the change in migration pattern suggested an important role for Grg4. Clonal misexpression of Grg4 resulted in cells migrating to laminae h-j of the SGFS. Massive misexpression of Grg4 resulted in disruption of laminae that were formed by early migratory cells, in particular lamina g of the SGFS. Application of Grg4 morpholino antisense oligonucleotide or the misexpression of a dominant-negative form of Grg4 exerted the opposite effect. We concluded that Grg4 may direct tectal postmitotic cells to follow a late migratory pathway.
SnailprecedesSlugin the genetic cascade required for the specification and migration of theXenopusneural crest
Authors: Aybar Manuel J. , Nieto M. Angela , Mayor Roberto
Published: January 2003

The complex sequence of inductive events responsible for the generation of the neural crest at the border between the neural plate and the epidermis,triggers a genetic cascade involving several families of transcription factors. Two members of the Snail family, Snail andSlug, have both been implicated in this cascade. In chick andXenopus, loss- and gain-of-function experiments have provided evidence that Slug plays a key role in neural crest development. However, in contrast to the chick, Snail rather than Slug is expressed in the premigratory neural crest in the mouse and, in Xenopus,Snail precedes Slug expression in this population. Thus, in order to study the function of Snail in neural crest development inXenopus, we have carried out conditional gain- and loss-of-function experiments using different Snail constructs fused to a glucocorticoid receptor element.

We show that Snail is able to induce the expression ofSlug and all other neural crest markers tested (Zic5, FoxD3,Twist and Ets1) at the time of specification. This activation is observed in whole embryos and in animal caps, in the absence of neural plate and mesodermal markers. We show that Snail is required for neural crest specification and migration and that it works as a transcriptional repressor. These functions have been previously attributed to Slug. However, Slug alone is unable to induce other neural crest markers in animal cap assays, and we show that Snail and Slug can be functionally equivalent when tested in overexpression studies. This suggests that, in Xenopus embryos, at least some of the functions previously attributed to Slug can be carried out by Snail. This is additionally supported by rescue experiments in embryos injected with dominant-negative constructs that indicate that Snail lies upstream of Slug in the genetic cascade leading to neural crest formation and that it plays a key role in crest development.
TheRADICLELESS1gene is required for vascular pattern formation in rice
Authors: Scarpella Enrico , Rueb Saskia , Meijer Annemarie H.
Published: January 2003

The molecular mechanisms through which the complex patterns of plant vascular tissues are established are largely unknown. The highly ordered, yet simple, striate array of veins of rice leaves represents an attractive system to study the dynamics underlying pattern formation. Here we show that mutation in the RADICLELESS1 (RAL1) gene results in distinctive vascular pattern defects. In ral1 embryonic scutella, secondary veins are absent and in the prematurely aborted and discontinuous primary veins,cells are misaligned to each other. In ral1 leaves, longitudinal and commissural (transverse) veins display altered spacing and the commissural veins additionally show atypical branching and interruptions in their continuity. The vascular pattern alterations of ral1 occur in the context of normally shaped leaf primordia. Anatomical inspection and analysis of the expression of the procambium specification marker Oshox1-GUS and of the auxin-inducible reporter DR5-GUS demonstrates that all the vascular patterning aberrations of ral1 originate from defects in the procambium, which represents the earliest identifiable stage of vascular development. Furthermore, the ral1 mutant is unique in that procambium formation in leaf primordium development is delayed. Finally, the ral1 vascular patterning distortions are associated with a defective response to auxin and with an enhanced sensitivity to cytokinin. ral1 is the first mutant impaired in both procambium development and vascular patterning to be isolated in a monocot species.
Sex-lethalsplicing autoregulation in vivo: interactions between SEX-LETHAL, the U1 snRNP and U2AF underlie male exon skipping
Authors: Nagengast Alexis A. , Stitzinger Shane M. , Tseng Chin-Hsiu , Mount Stephen M. , Salz Helen K.
Published: January 2003

Alternative splicing of the Sex-lethal pre-mRNA has long served as a model example of a regulated splicing event, yet the mechanism by which the female-specific SEX-LETHAL RNA-binding protein prevents inclusion of the translation-terminating male exon is not understood. Thus far, the only general splicing factor for which there is in vivo evidence for a regulatory role in the pathway leading to male-exon skipping is sans-fille(snf), a protein component of the spliceosomal U1 and U2 snRNPs. Its role, however, has remained enigmatic because of questions about whether SNF acts as part of an intact snRNP or a free protein. We provide evidence that SEX-LETHAL interacts with SANS-FILLE in the context of the U1 snRNP, through the characterization of a point mutation that interferes with both assembly into the U1 snRNP and complex formation with SEX-LETHAL. Moreover, we find that SEX-LETHAL associates with other integral U1 snRNP components, and we provide genetic evidence to support the biological relevance of these physical interactions. Similar genetic and biochemical approaches also link SEX-LETHAL with the heterodimeric splicing factor, U2AF. These studies point specifically to a mechanism by which SEX-LETHAL represses splicing by interacting with these key splicing factors at both ends of the regulated male exon. Moreover,because U2AF and the U1 snRNP are only associated transiently with the pre-mRNA during the course of spliceosome assembly, our studies are difficult to reconcile with the current model that proposes that the SEX-LETHAL blocks splicing at the second catalytic step, and instead argue that the SEX-LETHAL protein acts after splice site recognition, but before catalysis begins.