bluuebunny/crossref_metadata_2025 huggingface dataset:
Sympathetic Neural Activation in Nondiabetic Metabolic Syndrome and Its Further Augmentation by Hypertension
Authors: Huggett Robert J. , Burns Joanna , Mackintosh Alan F. , Mary David A.S.G.
Published: November 2004

Hypertension is a major cardiovascular risk factor in the metabolic syndrome (MS) in which the presence of insulin resistance, glucose intolerance, abnormal lipoprotein metabolism, and central obesity all confer an increased risk. Because essential hypertension (EHT), insulinemia, and visceral fat are associated with sympathetic hyperactivity, which is itself known to increase cardiovascular risk, the aim of this study was to see if MS is a state of sympathetic nerve hyperactivity and if the additional presence of EHT intensifies this hyperactivity. In 69 closely matched subjects, comprising hypertensive MS (MS+EHT, 18), normotensive MS (MS-EHT, 17), hypertensives without MS (EHT, 16), and normotensive controls without MS (NC, 18), we measured resting muscle sympathetic nerve activity (MSNA) as assessed from multiunit discharges and from single units with defined vasoconstrictor properties (s-MSNA). The s-MSNA in MS+EHT (76±3.1 impulses/100 beats) was greater (at least
P
<0.01) than in MS-EHT (62±3.2 impulses/100 beats) and in EHT (60±2.3 impulses/100 beats), and all these were significantly greater (at least
P
<0.01) than in NC (46±2.7 impulse/100 beats). The multi-unit MSNA followed a similar trend. These findings suggest that MS is a state of sympathetic nerve hyperactivity and that the additional presence of hypertension further intensifies this hyperactivity. The degree of sympathetic hyperactivity seen in this study could be argued at least partly to contribute to the higher cardiovascular risk and metabolic abnormalities seen in MS+EHT patients.
Evidence from the small and large ribosomal RNA structure suggests that Anoplostoma rectospiculum Gal'tsova, 1976 (Nematoda: Anoplostomatidae) is a member of the superfamily Enoploidea, not Oncholaimoidea
Authors: Pegova Anna N. , Krasnova Elena D. , Aleshin Vladimir V.
Published: November 2004

Analyses of the primary structure of the 18S rRNA gene and D3 segment of the
28S rRNA, as well as evidence from the secondary structure of the SSU rRNA
V7 region, suggest that Anoplostoma rectospiculum (Anoplostomatidae) has
closer relationships to the family Enoplidae than to the Oncholaimidae. In
phylogenetic trees derived from full length SSU rRNA gene and partial LSU
rRNA gene (D3 expansion segment) sequence analyses, A. rectospiculum
exhibits long branches. The associated artefacts of long branch attraction
(LBA) are circumvented because of the presence of an undoubted molecular
synapomorphy – a low homoplastic 1. b. p. insertion in helix 43 of the SSU
rRNA which is shared jointly by Anoplostomatidae and Enoplidae. Analysis of
low homoplastic apomorphic characters is considered to be a tool for testing
phylogenies against LBA artefacts.
A Dutch contribution to knowledge on phytosanitary risk and host status of various crops for Meloidogyne chitwoodi Golden et al., 1980 and M. fallax Karssen, 1996: an overview
Authors: den Nijs Loes , Brinkman Henk , van der Sommen Anton
Published: November 2004

The results of experiments, performed in The Netherlands during the last
decade, on the host range of Meloidogyne chitwoodi and M. fallax are
presented and discussed. Opinions are expressed on the host status of the
tested plants and the phytosanitary status of the commercial product
(defined as that part of the plant that enters trade) separately, as
interest for both categories may differ. Information for each category is
given for a variety of plants such as vegetables, arable crops, flowering
bulbs and plants, and ornamental plants and trees. Data obtained from
glasshouse experiments are given in a separate table. Many plants are a good
host for one or both nematode species, and the commercial product, such as
some bulbs and potatoes, might form a phytosanitary risk as a carrier of the
juveniles inside the product, this risk being increased when that commercial
product has roots.
Two new species of the genus Aphanonchus Coomans & Raski, 1991 (Nematoda: Aphanolaimidae) and a revised taxonomy of the genus
Authors: Holovachov Oleksandr , Sturhan Dieter
Published: November 2004

Two new species of Aphanonchus are described from Germany and Ivory Coast.
Aphanonchus europaeus sp. n., from Germany, is best characterised by 1.1-1.4
mm long body, presence of 50-96 lateral epidermal glands; female without
neck setae, with straight vagina without sclerotisations and three to nine
prevulval alveoli; male with a pair of neck setae, 15 tubular and 20
alveolar supplements, one pair of precloacal and four pairs of caudal setae,
39 μm long spicules. Aphanonchus africanus sp. n., from Ivory Coast, is
characterised by 1.0-1.3 mm long body, presence of 37 to 71 lateral
epidermal glands; female with a pair of neck setae, straight to slightly
sinuous vagina without sclerotisations, and without alveoli; male with a
pair of neck setae, 12-18 tubular and 54-80 alveolar supplements, a pair of
precloacal and four pairs of caudal setae, 35.5-43 μm long spicules.
Morphological data, based on specimens of A. bayensis from Costa Rica, A.
multipapillatus from Colombia and Suriname, A. obesus from Ivory Coast and
the type locality in Vietnam, and type specimens of A. longiceras, are
presented and supplement the descriptions of these four species. An emended
diagnosis and a revised classification of Aphanonchus are proposed and a key
to the species of the genus is provided.
Two Ways of Articulating Outsider's Knowledge of Polynesian Culture and Religion: Melville's Typee and Mardi
Authors: Despland Michel
Published: November 2004

Two of Melville's early works are contrasting attempts to report on what he saw and experienced during his stay in some islands of the South Pacific. Typee is presented as a sober, philosophical account of mores and religion, thus in keeping with the more ethnographic interests of travelers's reports. Mardi is an avowed work of fiction. While cannibalism serves to focus interest in the first, human sacrifice has this function in the second. Melville could find previous authors to support his approach in the first book but, even though he studied available works on mythologies, found no scholarship to help with the second issue. It is argued that the second work, albeit a fiction, makes the greater cognitive advance and helps discern the perils scholars had to face in the colonialist era.
Help Seeking for Personal Concerns About Developing Alzheimer’s Disease
Authors: Hodgson Lynne Gershenson , Cutler Stephen J.
Published: November 2004

This study examined the patterns and predictors of help-seeking behavior for personal concerns about developing Alzheimer’s disease (AD) among middle-aged persons. Data were obtained from a survey of two subsamples of 40- to 60-year-old adults with concerns about AD: (a) 99 adult children with a living parent with a diagnosis of probable AD and(b)70 adults in a matched group with no parental history of AD. Descriptive analyses of the types and levels of help seeking show that respondents who are concerned about developing AD take their fears mainly to their informal rather than formal networks. Bivariate and multivariate analyses identified significant correlates of help seeking within three clusters: memory assessment, AD experience, and sociodemographics. The most robust predictors were aspects of AD experience. Understanding the patterns and correlates of help seeking for AD concerns can help health care professionals to develop more effective models of early intervention with implications for early detection of the disease.
The Image of the Waterfront in Rio de Janeiro
Authors: Iwata Nara , del Rio Vicente
Published: November 2004

Postmodernity and economic globalization incite countries, regions, and cities to compete for investments, consumers, and resources. In aspiring for a new position in this global market, cities utilize new urban practices that lead them to rediscover and reinvent identities and traditions. In Rio de Janeiro, the mythical dimension of the South Zone is inseparably incorporated to its identity. In evaluating the history of the imagery linked to the beaches and the projects for the waterfront, one may observe a social construction of a reality that is marked by a continuous redesigning of symbols but also by a discontinuity in the history of urban interventions. Although tourism and marketing continually praise the waterfront as a fundamental factor in the image of the city, a continuous public management process never really existed. The city managers must understand the beaches, the waterfront, and development along the shoreline as important resources in a continuous process of social construction of a reality that should not only address their images as commodities but should treat them as inseparable from the city’s daily public and social lives.
The Cultural Bases of Volunteering: Understanding and Predicting Attitudinal Differences Between Flemish Red Cross Volunteers
Authors: Hustinx Lesley , Lammertyn Frans
Published: November 2004

This article presents an empirical evaluation of the current debate on the changing nature of volunteering in the light of sociological modernization theories. Focusing on the cultural bases of volunteerism, a representative sample of 652 Flemish Red Cross volunteers is grouped according to a multidimensional set of attitudinal measures. The Unconditional, Critical, Reliable, and Distant dispositional clusters that emerge from the analysis cohere with distinct patterns of volunteering, ranging from core to peripheral volunteer positions. Furthermore, both cultural modernization indicators and organizational features account for the dispositional variations observed. Although the analysis conducted clearly reveals the surplus value of a multidimensional sight on volunteering, the research outcomes warn against a too-strong focus on “grand modernization narratives.” The cultural bases of Flemish Red Cross volunteering may best be understood in terms of a threefold dynamic: Differences in cultural frames of reference intervene with life cycle effects and processes of organizational socialization.
Civic Service Worldwide: Defining a Field, Building a Knowledge Base
Authors: McBride Amanda Moore , Sherraden Michael , Benítez Carlos , Johnson Elizabeth
Published: November 2004

Civic service appears to be a global phenomenon. The growth of service may warrant a distinct field of study in which a comparative knowledge base could inform development and implementation of policies and programs. In this article, the authors summarize results of a global assessment of civic service. Searching by country and using information from organizational memberships, publications, and the Internet, 210 civic service programs were identified in 57 countries. This study has many limitations, raising more questions than it answers. Nonetheless, it is the first worldwide empirical glimpse of service, shedding light on several key questions: What are the current status and forms of civic service? What are its structures, goals, and effects? This introductory article of the special issue frames these questions for consideration by the authors, who identify historical and cultural determinants, forms, and mediators of civic service in different regions of the world.
Online Inquiry of Public Selves: Methodological Considerations
Authors: Broad Kendal L. , Joos Kristin E.
Published: November 2004

This article methodologically considers how to conduct online inquiry about the production of deprivatized selves. It begins by discussing how online selves can be understood as public selves produced under the auspices of particular local cultures on the Internet. Embedded within this argument is the authors’ assertion that methods for inquiring about the production of public selves offline (fieldwork and active interviewing) are amenable to online environments. The focus of the article is a discussion of how the authors tried to adopt such strategies of inquiry to an online arena. A methodological conundrum shared by the two studies discussed—the struggle between doing active inquiry about the dynamics of self-construction and maintaining the “safe space” expected in particular types of online arenas of self-construction—is highlighted. The article concludes by suggesting that future inquiry of online public selves will likely face similar challenges.
Searching Self-Image: Identities To Be Self-Evident
Authors: Rolling James Haywood
Published: November 2004

Naming can alternatively be a definition of identity or a source of stigma. Un-naming can alter a story and serve to unhinge fixed definitions, initiating a democratic discourse that finds its own way of escaping the thrall of hegemony and dominating canons. Can qualitative research serve to un-name axiomatic frameworks of identity? This article is written to follow up to the author’s Messing Around With Identity Constructs and continues his effort to establish the efficacy of a poststructural and poetic aesthetic in research writing.
Academic Triage: Challenges Confronting College Preparation Programs
Authors: Tierney William G.
Published: November 2004

By way of portraiture, the author recounts his interactions with three young adults engaged in a precollege outreach program. By contextualizing the students’ experiences, he provides insight into the emotions, needs, and educational challenges faced by students in high school intervention programs. The findings point to the necessity of recognizing the social context in which college preparation programs occur, the importance of offering systematic and sustained support to students, and the embedded nature of college preparation programs requiring coordinated and comprehensive communication across high schools, universities, and outreach programs.
Circles of Nineteen: Teaching in the Aftermath of September 11th
Authors: Tillmann-Healy Lisa M.
Published: November 2004

Using poetic form, the author chronicles the class period following September 11, 2001, when a student’s queries sparked complex thoughts and intense questioning. This piece opens a space for educators to reflect on emotional and ethical responsibilities during frightening and uncertain times.
The InDeVal insertion/deletion evaluation tool: a program for finding target regions in DNA sequences and for aiding in sequence comparison
Authors: Stoneberg Holt Sierra D , Holt Jason A
Published: November 2004

Background

The program InDeVal was originally developed to help researchers find known regions of insertion/deletion activity (with the exception of isolated single-base indels) in newly determined Poaceae trn L-F sequences and compare them with 533 previously determined sequences. It is supplied with input files designed for this purpose. More broadly, the program is applicable for finding specific target regions (referred to as "variable regions") in DNA sequence. A variable region is any specific sequence fragment of interest, such as an indel region, a codon or codons, or sequence coding for a particular RNA secondary structure.

Results

InDeVal input is DNA sequence and a template file (sequence flanking each variable region). Additional files contain the variable regions and user-defined messages about the sequence found within them (e.g., taxa sharing each of the different indel patterns).

Variable regions are found by determining the position of flanking sequence (referred to as "conserved regions") using the LPAM (Length-Preserving Alignment Method) algorithm. This algorithm was designed for InDeVal and is described here for the first time.

InDeVal output is an interactive display of the analyzed sequence, broken into user-defined units. Once the user is satisfied with the organization of the display, the information can be exported to an annotated text file.

Conclusions

InDeVal can find multiple variable regions simultaneously (28 indel regions in the Poaceae trn L-F files) and display user-selected messages specific to the sequence variants found. InDeVal output is designed to facilitate comparison between the analyzed sequence and previously evaluated sequence. The program's sensitivity to different levels of nucleotide and/or length variation in conserved regions can be adjusted. InDeVal is currently available for Windows in Additional file 1 or from http://www.sci.muni.cz/botany/elzdroje/indeval/.
Cross-species hybridisation of human and bovine orthologous genes on high density cDNA microarrays
Authors: Adjaye James , Herwig Ralf , Herrmann Doris , Wruck Wasco , BenKahla Alia , Brink Thore C , Nowak Monika , Carnwath Joseph W , Hultschig Claus , Niemann Heiner , Lehrach Hans
Published: November 2004

Background

Cross-species gene-expression comparison is a powerful tool for the discovery of evolutionarily conserved mechanisms and pathways of expression control. The usefulness of cDNA microarrays in this context is that broad areas of homology are compared and hybridization probes are sufficiently large that small inter-species differences in nucleotide sequence would not affect the analytical results. This comparative genomics approach would allow a common set of genes within a specific developmental, metabolic, or disease-related gene pathway to be evaluated in experimental models of human diseases. The objective of this study was to investigate the feasibility and reproducibility of cross-species analysis employing a human cDNA microarray as probe.

Results

As a proof of principle, total RNA derived from human and bovine fetal brains was used as a source of labelled targets for hybridisation onto a human cDNA microarray composed of 349 characterised genes. Each gene was spotted 20 times representing 6,980 data points thus enabling highly reproducible spot quantification. Employing high stringency hybridisation and washing conditions, followed by data analysis, revealed slight differences in the expression levels and reproducibility of the signals between the two species. We also assigned each of the genes into three expression level categories- i.e. high, medium and low. The correlation co-efficient of cross hybridisation between the orthologous genes was 0.94. Verification of the array data by semi-quantitative RT-PCR using common primer sequences enabled co-amplification of both human and bovine transcripts. Finally, we were able to assign gene names to previously uncharacterised bovine ESTs.

Conclusions

Results of our study demonstrate the harnessing and utilisation power of comparative genomics and prove the feasibility of using human microarrays to facilitate the identification of co-expressed orthologous genes in common tissues derived from different species.
Neural stem cells express melatonin receptors and neurotrophic factors: colocalization of the MT1receptor with neuronal and glial markers
Authors: Niles Lennard P , Armstrong Kristen J , Rincón Castro Lyda M , Dao Chung V , Sharma Rohita , McMillan Catherine R , Doering Laurie C , Kirkham David L
Published: November 2004

Background

In order to optimize the potential benefits of neural stem cell (NSC) transplantation for the treatment of neurodegenerative disorders, it is necessary to understand their biological characteristics. Although neurotrophin transduction strategies are promising, alternative approaches such as the modulation of intrinsic neurotrophin expression by NSCs, could also be beneficial. Therefore, utilizing the C17.2 neural stem cell line, we have examined the expression of selected neurotrophic factors under different in vitro conditions. In view of recent evidence suggesting a role for the pineal hormone melatonin in vertebrate development, it was also of interest to determine whether its G protein-coupled MT1 and MT2 receptors are expressed in NSCs.

Results

RT-PCR analysis revealed robust expression of glial cell-line derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in undifferentiated cells maintained for two days in culture. After one week, differentiating cells continued to exhibit high expression of BDNF and NGF, but GDNF expression was lower or absent, depending on the culture conditions utilized. Melatonin MT1 receptor mRNA was detected in NSCs maintained for two days in culture, but the MT2 receptor was not seen. An immature MT1 receptor of about 30 kDa was detected by western blotting in NSCs cultured for two days, whereas a mature receptor of about 40 – 45 kDa was present in cells maintained for longer periods. Immunocytochemical studies demonstrated that the MT1 receptor is expressed in both neural (β-tubulin III positive) and glial (GFAP positive) progenitor cells. An examination of the effects of melatonin on neurotrophin expression revealed that low physiological concentrations of this hormone caused a significant induction of GDNF mRNA expression in NSCs following treatment for 24 hours.

Conclusions

The phenotypic characteristics of C17.2 cells suggest that they are a heterogeneous population of NSCs including both neural and glial progenitors, as observed under the cell culture conditions used in this study. These NSCs have an intrinsic ability to express neurotrophic factors, with an apparent suppression of GDNF expression after several days in culture. The detection of melatonin receptors in neural stem/progenitor cells suggests involvement of this pleiotropic hormone in mammalian neurodevelopment. Moreover, the ability of melatonin to induce GDNF expression in C17.2 cells supports a functional role for the MT1 receptor expressed in these NSCs. In view of the potency of GDNF in promoting the survival of dopaminergic neurons, these novel findings have implications for the utilization of melatonin in neuroprotective strategies, especially in Parkinson's disease.
An evaluation of UV protection imparted by cotton fabrics dyed with natural colorants
Authors: Sarkar Ajoy K
Published: November 2004

Background

The ultraviolet properties of textiles dyed with synthetic dyes have been widely reported in literature. However, no study has investigated the ultraviolet properties of natural fabrics dyed with natural colorants. This study reports the Ultraviolet Protection Factor (UPF) of cotton fabrics dyed with colorants of plant and insect origins.

Methods

Three cotton fabrics were dyed with three natural colorants. Fabrics were characterized with respect to fabric construction, weight, thickness and thread count. Influence of fabric characteristics on Ultraviolet Protection Factor was studied. Role of colorant concentration on the ultraviolet protection factor was examined via color strength analysis.

Results

A positive correlation was observed between the weight of the fabric and their UPF values. Similarly, thicker fabrics offered more protection from ultraviolet rays. Thread count appears to negatively correlate with UPF. Dyeing with natural colorants dramatically increased the protective abilities of all three fabric constructions. Additionally, within the same fabric type UPF values increased with higher depths of shade.

Conclusion

Dyeing cotton fabrics with natural colorants increases the ultraviolet protective abilities of the fabrics and can be considered as an effective protection against ultraviolet rays. The UPF is further enhanced with colorant of dark hues and with high concentration of the colorant in the fabric.
In vivogene targeting of IL-3 into immature hematopoietic cells through CD117 receptor mediated antibody gene delivery
Authors: Chapel Alain , Deas Olivier , Bensidhoum Morad , François Sabine , Mouiseddine Moubarak , Poncet Pascal , Dürrbach Antoine , Aigueperse Jocelyne , Gourmelon Patrick , Gorin Norbert C , Hirsch François , Thierry Dominique
Published: November 2004

Background

Targeted gene transfection remains a crucial issue to permit the real development of genetic therapy. As such, in vivo targeted transfection of specific subsets of hematopoietic stem cells might help to sustain hematopoietic recovery from bone marrow aplasia by providing local production of growth factors.

Methods

Balb/C mice were injected intravenously, with an anti-mouse c-kit (CD117) monoclonal antibody chemically coupled to a human IL-3 gene-containing plasmid DNA. Mice were sacrificed for tissue analyses at various days after injection of the conjugates.

Results

By ELISA, the production of human IL-3 was evidenced in the sera of animals 5 days after treatment. Cytofluorometric analysis after in vivo transfection of a reporter gene eGFP demonstrated transfection of CD117+/Sca1+ hematopoietic immature cells. By PCR analysis of genomic DNA and RNA using primer specific pIL3 sequences, presence and expression of the human IL-3-transgene were detected in the bone marrow up to 10 days in transfected mice but not in control animals.

Conclusions

These data clearly indicate that antibody-mediated endocytosis gene transfer allows the expression of the IL-3 transgene into hematopoietic immature cells, in vivo. While availability of marketed recombinant growth factors is restricted, this targeting strategy should permit delivery of therapeutic genes to tissues of interest through systemic delivery. In particular, the ability to specifically target growth factor expression into repopulating hematopoietic stem cells may create new opportunities for the treatment of primary or radiation-induced marrow failures.
Human cytomegalovirus inhibits the migration of immature dendritic cells by down-regulating cell-surface CCR1 and CCR5
Authors: Varani Stefania , Frascaroli Giada , Homman-Loudiyi Mohammed , Feld Sari , Landini Maria Paola , Söderberg-Nauclér Cecilia
Published: November 2004

Dendritic cells (DC) play a key role in the host immune response to infections. Human cytomegalovirus (HCMV) infection can inhibit the maturation of DC and impair their ability to stimulate T cell proliferation and cytotoxicity. In this study, we assessed the effects of HCMV infection on the migratory behavior of human DC. The HCMV strain TB40/E inhibited the migration of immature monocyte-derived DC in response to inflammatory chemokines by 95% 1 day after infection. This inhibition was mediated by early viral replicative events, which significantly reduced the cell-surface expression of CC chemokine receptor 1 (CCR1) and CCR5 by receptor internalization. HCMV infection also induced secretion of the inflammatory chemokines CC chemokine ligand 3 (CCL3)/macrophage inflammatory protein-1α (MIP-1α), CCL4/MIP-1β, and CCL5/regulated on activation, normal T expressed and secreted (RANTES). Neutralizing antibodies for these chemokines reduced the effects of HCMV on chemokine receptor expression and on DC migration by ∼60%. Interestingly, the surface expression of the lymphoid chemokine receptor CCR7 was not up-regulated after HCMV infection on immature DC, and immature-infected DC did not migrate in response to CCL19/MIP-3β. These findings suggest that blocking the migratory ability of DC may be a potent mechanism used by HCMV to paralyze the early immune response of the host.
Higher Mortality After Allogeneic Peripheral-Blood Transplantation Compared With Bone Marrow in Children and Adolescents: The Histocompatibility and Alternate Stem Cell Source Working Committee of the International Bone Marrow Transplant Registry
Authors: Eapen Mary , Horowitz Mary M. , Klein John P. , Champlin Richard E. , Loberiza Fausto R. , Ringdén Olle , Wagner John E.
Published: November 2004

Purpose

Peripheral-blood stem cells (PBSC) may be used as an alternative to bone marrow (BM) for allogeneic transplantation. Despite lack of data on PBSC transplantation in children, there has been a change in clinical practice, with increasing numbers of children receiving PBSC allografts.

Patients and Methods

We compared the results of 143 PBSC and 630 BM transplants from human leukocyte antigen–identical sibling donors in children aged 8 to 20 years with acute leukemia. PBSC transplant recipients were older, and were more likely to have advanced leukemia, receive growth factors post-transplantation, and have undergone transplantation more recently. Risks of acute and chronic graft-versus-host disease (GVHD), treatment-related mortality, relapse, treatment failure (relapse or death), and overall mortality were compared using Cox proportional hazards regression to adjust for potentially confounding factors.

Results

Hematopoietic recovery was faster after PBSC transplantation. Risks of grade 2 to 4 acute GVHD were similar, but chronic GVHD risk was higher after PBSC transplantation (relative risk [RR], 1.85; 95% CI, 1.28 to 2.66; P = .001). In contrast to reports in adults, treatment-related mortality (RR, 1.89; 95% CI, 1.28 to 2.80; P = .001), treatment failure (RR, 1.31; 95% CI, 1.03 to 1.68; P = .03), and mortality (RR, 1.38; 95% CI, 1.07 to 1.79; P = .01) were higher after PBSC transplantation. Risks of relapse were similar.

Conclusion

These data suggest poorer outcomes after PBSC compared with BM transplantation in children after adjusting for relevant risk factors. Given the trend toward increased use of PBSC allografts in children, prospective clinical trials are required to determine their appropriate role in this group of patients.
Adhesion-contractile balance in myocyte differentiation
Authors: Griffin Maureen A. , Sen Shamik , Sweeney H. Lee , Discher Dennis E.
Published: November 2004

Tissue cells generally pull on their matrix attachments and balance a quasi-static contractility against adequate adhesion, but any correlation with and/or influence on phenotype are not yet understood. Here, we begin to demonstrate how differentiation state couples to actomyosin-based contractility through adhesion and substrate compliance. Myotubes are differentiated from myoblasts on collagen-patterned coverslips that allow linear fusion but prevent classic myotube branching. Post-fusion, myotubes adhere to the micro-strips but lock into a stress fiber-rich state and do not differentiate significantly further. In contrast, myotubes grown on top of such cells do progress through differentiation, exhibiting actomyosin striations within one week. A compliant adhesion to these lower cells is suggested to couple to contractility and accommodate the reorganization needed for upper cell striation. Contractility is assessed in these adherent cells by mechanically detaching one end of the myotubes. All myotubes, whether striated or not, shorten with an exponential decay. The cell-on-cell myotubes relax more, which implies a greater contractile stress. The non-muscle myosin II inhibitor blebbistatin inhibits relaxation for either case. Myotubes in culture are thus clearly prestressed by myosin II, and this contractility couples to substrate compliance and ultimately influences actomyosin striation.
Organization and pairing of meiotic chromosomes in the ciliateTetrahymena thermophila
Authors: Loidl Josef , Scherthan Harry
Published: November 2004

During meiotic prophase in the ciliate Tetrahymena thermophila micronuclei dramatically elongate and form thread-like crescents. The arrangement of the chromosomes within the crescent as well as the timing of chromosome pairing and recombination with respect to the elongation process have been subjects of ongoing debate. Here, we addressed these issues by means of fluorescence in situ hybridization, labeling of individual chromosomes by BrdU (BrdU-painting) and by immunostaining of the recombination protein, Rad51. BrdU-painting indicated that chromosomes are arranged as parallel bundles within the crescent, and telomere-directed fluorescent in situ hybridization (FISH) revealed that most if not all telomeres are assembled near one end of the developing crescent. Prior to full crescent formation, Rad51 localizes to chromatin as numerous foci. Locus-specific FISH demonstrated that close pairing of homologues only occurs in the full crescent. Meiotic DNA double-strand break formation and the initiation of recombination thus seem to precede close pairing. A synaptonemal complex was not detected. We conclude that the chromosomes adopt a polarized arrangement within the crescent, probably resembling the classical bouquet arrangement. Furthermore, we propose that the elongated shape of meiotic micronuclei promotes the parallel arrangement of chromosomes and supports the juxtaposition of homologous regions in the absence of a synaptonemal complex. Several pieces of evidence indicate the presence of one to four chiasmata per bivalent, which would call for crossover interference to explain regular bivalent formation in spite of this low mean number. Tetrahymena might, therefore, pose a case of interference in the absence of a synaptonemal complex.
A variant histone H3 is enriched at telomeres in Trypanosoma brucei
Authors: Lowell Joanna E. , Cross George A. M.
Published: November 2004

Variant histones play critical roles in transcriptional activation and repression, DNA repair and chromosome segregation. We have identified HTV, a single-copy gene in Trypanosoma brucei encoding a variant form of histone H3 (H3V). H3V is present at discrete nuclear foci that shift over the course of the cell cycle and associate with the mitotic spindle, a pattern of localization reminiscent of that described previously for both mini-chromosomes and telomeres. By combining fluorescence in situ hybridization with indirect immunofluorescence, we confirmed that the H3V foci overlap with a 177-bp repetitive sequence element found predominantly in mini-chromosomes, as well as with the TTAGGG repeats that compose telomeres. Chromatin immunoprecipitation studies, however, reveal that only the telomeric repeat DNA is substantially enriched with H3V. HTV is not essential for viability, mini-chromosome segregation, telomere maintenance or transcriptional silencing at the telomere-proximal expression sites from which bloodstream-form T. brucei controls antigenic variation. We propose that H3V represents a novel class of histone H3 variant, a finding that has evolutionary implications.
On the influence of the initial tension of a strip with a rectangular hole on the stress concentration caused by additional loading
Authors: Akbarov S D , Yahnioglu N , Yucel A. M
Published: November 2004

The influence of the initial stretching of a simply supported plate strip containing a rectangular hole with rounded-off corners on the stress concentration around the hole caused by the bending of the strip under the action of uniformly distributed normal forces on the plane of its upper face is studied within the framework of the three-dimensional theory of elasticity under a plane-strain state. The mathematical formulation of the corresponding boundary value problems is presented. For the solution to these problems the finite element method is employed and for this purpose the validity of the constructed functional is proven. The material of the plate strip is selected as linear elastic, homogeneous and orthotropic. The numerical results are presented for the composite consisting of two alternating layers made from isotropic linear elastic materials.
Numerical studies of variations in the gap and finger width ratio and travelled distance for the driving force of a radio-frequency microelectromechanical system device using the dual boundary element method
Authors: Liao Y-S , Chyuan S-W , Chen J-T
Published: November 2004

For the comb-drive design of microelectromechanical systems (MEMSs), the driving force due to the electrostatic field is very important, and an accurate electrostatic analysis is essential and indispensable. For various gaps, finger width ratios and travelled distances of the comb drive of MEMSs, the dual boundary element method (DBEM) has become a better method than the domain-type finite element method because the DBEM can provide a complete solution in terms of boundary values, with substantial saving in modelling effort. In this article, the DBEM is used to simulate the fringing field around the edges of the fixed and movable fingers of the comb drive of an MEMS for diverse design cases, and many electrostatic problems for typical comb drive designs of MEMSs are analysed, investigated and compared with a widely used approximate method. Results show that the driving force is obviously dependent on the travelled distance, and the approximate method cannot work well for all travelled positions because there is an apparent error (not less than 10 per cent), especially at the beginning and ends of the range of travel. In addition, the smaller the gap between movable and fixed fingers, the larger the driving force is, and the error of approximate method also becomes more and more predominant as the gap decreases. The results also demonstrate that the difference between the DBEM and the approximate method effect due to finger width ratio is very small. Using the DBEM presented in this article, an accurate and reasonable electrostatic field can be obtained, and the follow-up control method of driving force for the comb drive of an MEMS can be implemented more precisely.
Dynamic stability of viscoelastic columns loaded by a follower force
Authors: Darabseh T T , Genin J
Published: November 2004

This paper analyses the motion of a linear viscoelastic column using the dynamic approach. The viscoelastic material is mathematically represented by the four-element model. Using this model as a recursion equation, the elastic, one-, two-, three- and four-element models are solved and their results compared. The stability analyses of these systems are investigated by studying the eigenvalues of the characteristic equations for the solution to the boundary value problems. The stability analyses determined the smallest value of the follower load beyond which the system, under a suitable disturbance, will perform oscillations with increasing amplitudes. The dynamic instability is found to occur in the form of flutter.

The effect of damping on the critical follower load is also examined. Three damping parameters are considered that affect the results. They are the damping coefficients related to a Maxwell unit, to a Kelvin unit and one appropriate to a combination of the two. The destabilization effects of viscosity are discussed.
Study of the effects of unsteady downstream conditions on the gas flow through a critical nozzle
Authors: Kim1 H-D , Kim J-H , Park K-A , Setoguchi T , Matsuo S
Published: November 2004

The present study addresses a computational result of unsteady gas flow through a critical nozzle. The axisymmetric unsteady compressible Navier-Stokes equations are solved using a finite volume method that makes use of the second-order upwind scheme for spatial derivatives and the multi-stage Runge-Kutta integral scheme for time derivatives. The steady solutions of the governing equation system are validated with the previous experimental data to ensure that the present computational method is valid to predict the critical nozzle flows. In order to simulate the effects of back-pressure fluctuations on the critical nozzle flows, an excited pressure oscillation with an amplitude and frequency is assumed downstream of the exit of the critical nozzle. The results obtained show that, for low Reynolds numbers, the unsteady effects of the pressure fluctuations can propagate upstream of the throat of the critical nozzle, thus giving rise to the applicable fluctuations in mass flow rate through the critical nozzle, while, for high Reynolds numbers, the pressure signals occurring at the exit of the critical nozzle do not propagate upstream beyond the nozzle throat. For a low Reynolds number, it is found that the sonic line near the throat of the critical nozzle markedly fluctuates with time, providing an important mechanism for pressure signals to propagate upstream of the nozzle throat, even in choked flow conditions. The present study is the first investigation to clarify the unsteady effects on the critical nozzle flows.
Performance analysis of air-lift pump design
Authors: Awari G K , Ardhapurkar P M , Wakde D G , Bhuyar L B
Published: November 2004

The air-lift pump is a well-established method for vertical transport of liquids and solid-liquid mixtures. The objectives of the present study are to evaluate the performance of a pump under predetermined operating conditions and to optimize the related parameters for the use of the pump for two-phase mixtures of air and water when a compressor is readily available.

This paper is focused on the general mathematical functions applicable to air-lift pump installations. The effect of various design parameters on the performance of air-lift pump is presented. A user-friendly computer program is developed on the basis of the optimization of influencing variables. This program will be useful for the design and installation of an air-lift pump handling air-water mixtures. A comparative study of an air-lift pump with a centrifugal pump handling two-phase mixtures is also discussed in the paper.
Modified nucleotides at the 5′ end of human U2 snRNA are required for spliceosomal E-complex formation
Authors: DÖNMEZ GIZEM , HARTMUTH KLAUS , LÜHRMANN REINHARD
Published: November 2004

U2 snRNA, a key player in nuclear pre-mRNA splicing, contains a 5′-terminal m3G cap and many internal modifications. The latter were shown in vertebrates to be generally required for U2 function in splicing, but precisely which residues are essential and their role in snRNP and/or spliceosome assembly is presently not clear. Here, we investigated the roles of individual modified nucleotides of HeLa U2 snRNA in pre-mRNA splicing, using a two-step in vitro reconstitution/complementation assay. We show that the three pseudouridines and five 2′O-methyl groups within the first 20 nucleotides of U2 snRNA, but not the m3G cap, are required for efficient pre-mRNA splicing. Individual pseudouridines were not essential, but had cumulative effects on U2 function. In contrast, four of five 2′O-methylations (at positions 1, 2, 12, and 19) were individually required for splicing. The in vitro assembly of 17S U2 snRNPs was not dependent on the presence of modified U2 residues. However, individual internal modifications were required for the formation of the ATP-independent early spliceosomal E complex. Our data strongly suggest that modifications within the first 20 nucleotides of U2 play an important role in facilitating the interaction of U2 with U1 snRNP and/or other factors within the E complex.
Long-Acting Injectable Risperidone
Authors: Ehret Megan J , Fuller Matthew A
Published: November 2004

OBJECTIVE

To review the pharmacology, pharmacokinetics, clinical efficacy, and safety profile of long-acting (LA) risperidone for the treatment of schizophrenia.

DATA SOURCES

Information was selected from PubMed (1965–July 2004). Applicable scientific posters were also used.

STUDY SELECTION AND DATA EXTRACTION

All published information on risperidone LA was considered. Material providing a comprehensive description was considered.

DATA SYNTHESIS

Risperidone LA is the first long-acting, injectable atypical antipsychotic. It is dosed at 25–50 mg every 2 weeks. Adverse effects are similar to those seen with oral risperidone. A short-term study showed that risperidone LA is better than placebo in reducing the signs and symptoms of schizophrenia, and a long-term trial showed that stable schizophrenic patients can be switched from either oral or other injectable antipsychotic medications to risperidone LA.

CONCLUSIONS

Risperidone LA is efficacious and safe in the treatment of schizophrenia.
First Patient-Centered Drug Information Service in Germany—A Descriptive Study
Authors: Maywald Ulf , Schindler Christoph , Krappweis Jutta , Kirch Wilhelm
Published: November 2004

BACKGROUND

The majority of patients have unmet drug information needs, and patients’ knowledge of their own treatment is often poor. This is a major obstacle to a more patient-centered healthcare system.

OBJECTIVE

To explore patterns of patients’ unmet drug information needs and outcomes of counseling patients by a drug and therapy information center (DTIC).

METHODS

We established the first German DTIC for patients. In this descriptive study, data obtained on callers within 24 months were analyzed. Questionnaires for gathering information about callers’ characteristics and the outcome of the advice were sent to all patients using the service after consultation. Data on all inquiries and evaluation sheets were documented and analyzed by a standardized database.

RESULTS

During 24 months, 2049 telephone calls were recorded. Patients’ unmet information needs were mainly related to adverse drug reactions/drug interactions (31.0%) and therapy information (27.2%). In 81.0% of the cases, patients’ uncertainties regarding their prescribed medications were reduced, 37.9% discussed the advice with their physician, and 18.3% reported a reduction of physician visits as a result of our advice. The patient–physician relationship remained mainly (70.6%) unaffected after our intervention.

CONCLUSIONS

The DTIC is useful as a source of medical expert advice. The service can help to reduce medication problems based on inadequate information and therefore avoid unnecessary healthcare utilization. With the knowledge provided, patients can participate in decisions affecting their own health. This procedure encourages greater confidence in the merits of drug therapy.
Does the cue help? Children's understanding of multiplicative concepts in different problem contexts
Authors: Squire Sarah , Davies Charlotte , Bryant Peter
Published: November 2004

Background: Understanding arithmetical principles is a key part of a conceptual understanding of mathematics. However, very little attention has been paid to children's understanding of multiplicative, as compared to additive, principles.

Aims: This study investigated(a) children's ability to use commutative and distributive cues to solve multiplication problems, (b) whether their ability to use these cues depends on the problem context, and(c) whether separate mechanisms might underlie children's understanding of commutativity and distributivity.

Sample: Twenty‐seven 9‐year‐olds (Year 5) and thirty‐two 10‐year‐olds (Year 6).

Methods: Forty‐eight multiplication problems (with a multiple‐choice response format) were presented to children. There were four types of problem: Commutative, Distributive, Combined commutative‐distributive(all preceded by a cue) and No cue problems. Each type of problem was presented in three different contexts: Isomorphism of measures, Area, and Cartesian product.

Results: Children demonstrated a good understanding of commutativity but a very poor understanding of distributivity. A common mistake in the distributive problems was to select the number that was one more, or one less, than the answer in the cue. Children's understanding of distributivity (butnot commutativity) seemed to depend on the problem context. Factor analysis suggested that separate factors underlie the ability to solve commutative and distributive problems.

Conclusions: Nine‐ and 10‐year‐olds understand commutativity, but are unable to use the distributive principle in multiplication. Their errors suggest that they may confuse some of the principles of multiplication with those of addition. When children do begin to understand the principle of distributivity, they most easily apply it in the context of Isomorphism of measures multiplication problems. The implications for mathematical education are discussed.