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Search Results: 1 - 10 of 8893 matches for " Ben Bolstad "
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Genetic aspects of Sj?gren's syndrome
Anne Bolstad, Roland Jonsson
Arthritis Research & Therapy , 2002, DOI: 10.1186/ar599
Abstract: Sj?gren's syndrome is an autoimmune exocrinopathy of unknown aetiology. It is a member of the group of inflammatory rheumatic disorders classified as connective tissue diseases. Clinical experience indicates not only an overlap among these disorders but also a close relationship of, for example, autoantibody profiles [1]. The genetic implications of this overlap has not been extensively explored, and the genetics behind Sj?gren's syndrome per se are not well characterized.There is no single disease-specific diagnostic criterion for Sj?gren's syndrome. For diagnosis, the most functional criteria are the recently modified European classification criteria, which include a list of exclusions [2]. In addition to the subjective symptoms of dry eyes and dry mouth, the following objective signs should be present: ocular signs by Schirmer's I test and/or Rose Bengal score; focal sialadenitis by histopathology; salivary gland involvement by either salivary scintigraphy, parotid sialography or unstimulated salivary flow; and autoantibodies of Ro/ Sj?gren syndrome antigen A (SSA) and/or La/Sj?gren syndrome antigen B (SSB) specificity.Sj?gren's syndrome occurs worldwide and in all ages. However, the peak incidence is in the fourth and fifth decades of life, with a female:male ratio of 9:1. A number of studies have shown great variation in the frequency of Sj?gren's syndrome (for review [3]). Prevalence studies have demonstrated that sicca symptoms and primary Sj?gren's syndrome affects a considerable percentage of the population, with precise numbers dependent on the age group studied and on the criteria used [4]. A cautious but realistic estimate from the studies presented thus far is that primary Sj?gren's syndrome is a disease with a prevalence not exceeding 0.6% of the general population (6/1000).Although generally considered a T-cell-mediated disease, potential mechanisms underlying Sj?gren's syndrome range from disturbances in apoptosis [5,6] to circulating autoantibodies
Recent Advances in Fluorescent Arylboronic Acids for Glucose Sensing
Jon Stefan Hansen,J?rn Bolstad Christensen
Biosensors , 2013, DOI: 10.3390/bios3040400
Abstract: Continuous glucose monitoring (CGM) is crucial in order to avoid complications caused by change in blood glucose for patients suffering from diabetes mellitus. The long-term consequences of high blood glucose levels include damage to the heart, eyes, kidneys, nerves and other organs, among others, caused by malign glycation of vital protein structures. Fluorescent monitors based on arylboronic acids are promising candidates for optical CGM, since arylboronic acids are capable of forming arylboronate esters with 1,2- cis-diols or 1,3-diols fast and reversibly, even in aqueous solution. These properties enable arylboronic acid dyes to provide immediate information of glucose concentrations. Thus, the replacement of the commonly applied semi-invasive and non-invasive techniques relying on glucose binding proteins, such as concanavalin A, or enzymes, such as glucose oxidase, glucose dehydrogenase and hexokinases/glucokinases, might be possible. The recent progress in the development of fluorescent arylboronic acid dyes will be emphasized in this review.
Causal Network Inference via Group Sparse Regularization
Andrew Bolstad,Barry Van Veen,Robert Nowak
Statistics , 2011, DOI: 10.1109/TSP.2011.2129515
Abstract: This paper addresses the problem of inferring sparse causal networks modeled by multivariate auto-regressive (MAR) processes. Conditions are derived under which the Group Lasso (gLasso) procedure consistently estimates sparse network structure. The key condition involves a "false connection score." In particular, we show that consistent recovery is possible even when the number of observations of the network is far less than the number of parameters describing the network, provided that the false connection score is less than one. The false connection score is also demonstrated to be a useful metric of recovery in non-asymptotic regimes. The conditions suggest a modified gLasso procedure which tends to improve the false connection score and reduce the chances of reversing the direction of causal influence. Computational experiments and a real network based electrocorticogram (ECoG) simulation study demonstrate the effectiveness of the approach.
Bioconductor: open software development for computational biology and bioinformatics
Robert C Gentleman, Vincent J Carey, Douglas M Bates, Ben Bolstad, Marcel Dettling, Sandrine Dudoit, Byron Ellis, Laurent Gautier, Yongchao Ge, Jeff Gentry, Kurt Hornik, Torsten Hothorn, Wolfgang Huber, Stefano Iacus, Rafael Irizarry, Friedrich Leisch, Cheng Li, Martin Maechler, Anthony J Rossini, Gunther Sawitzki, Colin Smith, Gordon Smyth, Luke Tierney, Jean YH Yang, Jianhua Zhang
Genome Biology , 2004, DOI: 10.1186/gb-2004-5-10-r80
Abstract: The Bioconductor project [1] is an initiative for the collaborative creation of extensible software for computational biology and bioinformatics (CBB). Biology, molecular biology in particular, is undergoing two related transformations. First, there is a growing awareness of the computational nature of many biological processes and that computational and statistical models can be used to great benefit. Second, developments in high-throughput data acquisition produce requirements for computational and statistical sophistication at each stage of the biological research pipeline. The main goal of the Bioconductor project is creation of a durable and flexible software development and deployment environment that meets these new conceptual, computational and inferential challenges. We strive to reduce barriers to entry to research in CBB. A key aim is simplification of the processes by which statistical researchers can explore and interact fruitfully with data resources and algorithms of CBB, and by which working biologists obtain access to and use of state-of-the-art statistical methods for accurate inference in CBB.Among the many challenges that arise for both statisticians and biologists are tasks of data acquisition, data management, data transformation, data modeling, combining different data sources, making use of evolving machine learning methods, and developing new modeling strategies suitable to CBB. We have emphasized transparency, reproducibility, and efficiency of development in our response to these challenges. Fundamental to all these tasks is the need for software; ideas alone cannot solve the substantial problems that arise.The primary motivations for an open-source computing environment for statistical genomics are transparency, pursuit of reproducibility and efficiency of development.High-throughput methodologies in CBB are extremely complex, and many steps are involved in the conversion of information from low-level information structures (for example,
A five-year prospective study of fatigue in primary Sj?gren's syndrome
Karstein Haldorsen, Ingvar Bjelland, Anne Bolstad, Roland Jonsson, Johan Brun
Arthritis Research & Therapy , 2011, DOI: 10.1186/ar3487
Abstract: A clinical and laboratory investigation of 141 patients fulfilling the American-European consensus criteria of pSS was undertaken in the period May 2004 to April 2005. Median time since diagnosis was 5.5 years. Examinations included the fatigue questionnaires: fatigue severity scale (FSS), fatigue visual analogue scale (VAS), functional assessment of chronic illness therapy - fatigue (FACIT-F) and medical outcome study short form-36 (SF-36) vitality, which were repeated in a follow-up investigation in January and February 2010.A total of 122 patients (87%) responded at both time-points. Thirty-five percent of patients experienced a clinically significant FSS increase. On the group level, fatigue measures did not change except that there was a slight deterioration in SF-36 vitality score. High serum anti-Sj?gren's syndrome A antigen (anti-SSA) showed weak associations with high baseline fatigue, and patients with increasing fatigue had lower baseline unstimulated whole salivary volume. Weak associations between increasing fatigue and serum immunoglobulin G (IgG), and the pro-inflammatory cytokine interleukin-17 (IL-17), were observed. Baseline sicca symptoms correlated with higher fatigue both at baseline and with increasing fatigue over time. Linear regression analysis did not identify any predictive ability of clinical or laboratory measures on fatigue change over time.Fatigue remained mainly unchanged over time. Using multivariate models did not reveal any clinical or laboratory predictors of fatigue change over time.Primary Sj?gren's syndrome (pSS) is a systemic rheumatic autoimmune disease targeting, in particular, exocrine glands, with eye and mouth dryness as classic symptoms. Extraglandular manifestations include arthritis, skin vasculitis and lymphoma [1]. Fatigue is a common complaint in pSS and other rheumatic disorders, as well as in malignancies and several other chronic conditions. Fatigue may be defined as "an overwhelming sense of tiredness, lack of e
Effect of calf stimulation on milk ejection in reindeer (Rangifer tarandus)
Hallvard Gj?stein,?ystein Holand,Tore Bolstad,Knut Hove
Rangifer , 2004,
Abstract: The objective of this study was to establish methods for stimulating the milk ejection in reindeer kept for milking purpose. Calves were used to stimulate milk does’ let down. In experiment 1, five does were allowed olfactory, acoustic and visual contact with their calves during milking, whereas four does were milked in isolation. The treatment of the groups was alternated every day during the eight days experiment. Olfactory, acoustic and visual contact with the calf did not influence the doe’s milk yield. The milk yield varied significantly between individual females within treatment (P < 0.01). In experiment 2, the calves were allowed to suckle their mother for a short period (two seconds) prior to milking being initiated. The same alternate design as in experiment 1 with groups consisting of three and two animals respectively was used, and the experiment lasted four days. The pre-suckling stimulation significantly increased the milk ejection measured as milk yield (P < 0.05), and the residual milk after the treatment was negectible. Moreover, the milk ejection varied between individual females within treatment (P < 0.05). We conclude that it is possible to achieve a complete milk removal by machine milking after the does have been pre-stimulated by suckling of calves. Olfactory, acoustic and visual contact with calves during milking failed to influence the milk ejection in this study. However, the results have to be interpreted with caution due to limited sample size. Abstract in Norwegian / Sammendrag: Form let med dette fors ket var pr ve ut ulike metoder for stimulere nedgivninga av melk hos rein. Kalvene ble tatt i bruk for stimulere nedgivninga. I fors k 1 hadde simla lyd-, lukt og synskontakt med kalven mens melkingen p gikk. Vi benyttet et ”switch back design” der fem simler hadde kontakt med kalven under melkingen og fire ble melket uten kontakt. Behandlingen ble byttet om annenhver dag i de tte dagene fors ket varte. Lyd-, lukt og synskontakt med kalven under melking hadde ingen innvirkning p melkemengden ved maskinmelking. Det var imidlertid individuell variasjon i hvor mye melk man oppn dde hos simlene (P < 0.01). I fors k 2 lot vi kalvene suge simlene en kort stund f r simlene ble melket. Kalven ble sluppet inn til simla og sugingen ble avbrutt etter to sekunder. Deretter ble simla f rt inn for maskinmelking. Fors ket varte i fire dager og vi benyttet samme ”switch back design” som i fors k 1, med grupper best ende av henholdsvis to og tre dyr. Stimuleringa med suging hadde en signifikant innvirkning p nedgivninga. (P < 0.05), o
International Market Expansion Strategies for High-Tech Firms: Examining the Importance of Different Partner Selection Criteria when Forming Strategic Alliances
?ystein Moen,Anette Bolstad,Vidar Pedersen,Ottar Bak?s
International Journal of Business and Management , 2009, DOI: 10.5539/ijbm.v5n1p20
Abstract: Newly established, technology-based firms entering international markets often have limited resources in terms of capabilities, time, and capital. As a consequence, these firms often use entry modes characterised by low resource commitment, including partnership agreements (strategic alliances). This paper, investigates which partner selection criteria that are important for this group of firms when they are selecting partners. Based on case studies of three Norwegian firms targeting the UK market, five selection criteria have been identified as important (trust, relatedness of business, access to networks, access to market knowledge, reputation), one has been identified as partly important (sharing of financial risk), and ten have been identified as having limited importance. Further, the paper discusses the implications of these results for managers of small firms entering international markets and presents recommendations for further research.
Quality assessment for short oligonucleotide microarray data
Julia Brettschneider,Francois Collin,Benjamin M. Bolstad,Terence P. Speed
Statistics , 2007,
Abstract: Quality of microarray gene expression data has emerged as a new research topic. As in other areas, microarray quality is assessed by comparing suitable numerical summaries across microarrays, so that outliers and trends can be visualized, and poor quality arrays or variable quality sets of arrays can be identified. Since each single array comprises tens or hundreds of thousands of measurements, the challenge is to find numerical summaries which can be used to make accurate quality calls. To this end, several new quality measures are introduced based on probe level and probeset level information, all obtained as a by-product of the low-level analysis algorithms RMA/fitPLM for Affymetrix GeneChips. Quality landscapes spatially localize chip or hybridization problems. Numerical chip quality measures are derived from the distributions of Normalized Unscaled Standard Errors and of Relative Log Expressions. Quality of chip batches is assessed by Residual Scale Factors. These quality assessment measures are demonstrated on a variety of datasets (spike-in experiments, small lab experiments, multi-site studies). They are compared with Affymetrix's individual chip quality report.
R2: Information or Noise? Textual Analysis Based on SSE E-Interaction  [PDF]
Ben Wang
Open Journal of Business and Management (OJBM) , 2019, DOI: 10.4236/ojbm.2019.72054
Abstract: The question whether R2 represents information or noise is still a fundamental question in the study of stock price synchronicity. There are two main difficulties. Firstly, the trait information of a company is hard to measure; Secondly, the investors’ sophistication is ignored when we discuss the effectiveness of market. Through the study of Chinese SSE E-interaction platform and the measurement by textual analysis method, this article argues that the improvement of investors’ sophistication has negative association with stock price synchronicity. This result is more salient in companies with lower opacity or with higher corporate governance. This paper contributes to the deepen understanding of stock price synchronicity and new method of measuring trait information of companies.
Blockade of lymphotoxin-beta receptor signaling reduces aspects of Sj?gren's syndrome in salivary glands of non-obese diabetic mice
Margaret K Gatumu, Kathrine Skarstein, Adrian Papandile, Jeffrey L Browning, Roy A Fava, Anne Bolstad
Arthritis Research & Therapy , 2009, DOI: 10.1186/ar2617
Abstract: The course of SS-like disease was followed in NOD mice that were given lymphotoxin-beta receptor-immunoglobulin fusion protein (LTβR-Ig) starting at 9 weeks of age. Treatment was given as a single weekly dose for 3, 7, or 10 weeks. Age-matched NOD mice treated with mouse monoclonal IgG1, or not treated at all, were used as controls. The severity of inflammation, cellular composition, and lymphoid neogenesis in the submandibular glands were determined by immunohistochemistry. Mandibular lymph nodes were also studied. Saliva flow rates were measured, and saliva was analyzed by a multiplex cytokine assay. The salivary glands were analyzed for CXCL13, CCL19, and CCL21 gene expression by quantitative polymerase chain reaction.Treatment with LTβR-Ig prevented the increase in size and number of focal infiltrates normally observed in this SS-like disease. Compared with the controls, the submandibular glands of LTβR-Ig-treated mice had fewer and smaller T- and B-cell zones and fewer high endothelial venules per given salivary gland area. Follicular dendritic cell networks were lost in LTβR-Ig-treated mice. CCL19 expression was also dramatically inhibited in the salivary gland infiltrates. Draining lymph nodes showed more gradual changes after LTβR-Ig treatment. Saliva flow was partially restored in mice treated with 10 LTβR-Ig weekly injections, and the saliva cytokine profile of these mice resembled that of mice in the pre-disease state.Our findings show that blocking the LTβR pathway results in ablation of the lymphoid organization in the NOD salivary glands and thus an improvement in salivary gland function.Sj?gren syndrome (SS) is a chronic autoimmune disorder characterized by lymphocytic infiltrates of the exocrine glands. Patients present clinical symptoms of dry eyes and dry mouth. The exocrinopathy may occur alone (primary SS) or in association with another autoimmune disorder (secondary SS) such as rheumatoid arthritis or systemic lupus erythematosus [1]. Inflammato
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