6,478 research outputs found
Mutation of Arabidopsis SPLICEOSOMAL TIMEKEEPER LOCUS1 Causes Circadian Clock Defects
The circadian clock plays a crucial role in coordinating plant metabolic and physiological functions with predictable environmental variables, such as dusk and dawn, while also modulating responses to biotic and abiotic challenges. Much of the initial characterization of the circadian system has focused on transcriptional initiation, but it is now apparent that considerable regulation is exerted after this key regulatory step. Transcript processing, protein stability, and cofactor availability have all been reported to influence circadian rhythms in a variety of species. We used a genetic screen to identify a mutation within a putative RNA binding protein (SPLICEOSOMAL TIMEKEEPER LOCUS1 [STIPL1]) that induces a long circadian period phenotype under constant conditions. STIPL1 is a homolog of the spliceosomal proteins TFP11 (Homo sapiens) and Ntr1p (Saccharomyces cerevisiae) involved in spliceosome disassembly. Analysis of general and alternative splicing using a high-resolution RT-PCR system revealed that mutation of this protein causes less efficient splicing of most but not all of the introns analyzed. In particular, the altered accumulation of circadian-associated transcripts may contribute to the observed mutant phenotype. Interestingly, mutation of a close homolog of STIPL1, STIP-LIKE2, does not cause a circadian phenotype, which suggests divergence in function between these family members. Our work highlights the importance of posttranscriptional control within the clock mechanism. © 2012 American Society of Plant Biologists. All rights reserved
Leaky fields from damaged shields
Journal ArticleIn a world where wireless devices appear to dominate society, it is wires that truly rule and connect our lives. Certainly the spread of cellular phones, Bluetooth technology, wireless sensor networks, and advances of ion-lithium battery capabilities have made common daily devices more disconnected and portable. However; at the end of the day we are reaching for wired chargers for power, transporting ourselves around in planes and car with extensive wiring, and living in homes still very connected with wires
Bacterial community profiles and Vibrio parahaemolyticus abundance in individual oysters and their association with estuarine ecology
Oysters naturally harbor the human gastric pathogen Vibrio parahaemolyticus, but the nature of this association is unknown. Because microbial interactions could influence the accumulation of V. parahaemolyticus in oysters, we investigated the composition of the microbiome in water and oysters at two ecologically unique sites in the Great Bay Estuary, New Hampshire using 16s rRNA profiling. We then evaluated correlations between bacteria inhabiting the oyster with V. parahaemolyticus abundance quantified using a most probable number (MPN) analysis. Even though oysters filter-feed, their microbiomes were not a direct snapshot of the bacterial community in overlaying water, suggesting they selectively accumulate some bacterial phyla. The microbiome of individual oysters harvested more centrally in the bay were relatively more similar to each other and had fewer unique phylotypes, but overall more taxonomic and metabolic diversity, than the microbiomes from tributary-harvested oysters that were individually more variable with lower taxonomic and metabolic diversity. Oysters harvested from the same location varied in V. parahaemolyticus abundance, with the highest abundance oysters collected from one location. This study, which to our knowledge is the first of its kind to evaluate associations of V. parahaemolyticus abundance with members of individual oyster microbiomes, implies that sufficient sampling and depth of sequencing may reveal microbiome members that could impact V. parahaemolyticus abundance
The Skills Framework for the Information Age: Engaging Stakeholders in ICT Curriculum Design
This paper reports on a research project, examining the role of the Skills Framework for the Information Age (SFIA) in Information and Communications Technology (ICT) curriculum design and management. A goal was to investigate how SFIA informs a top-down approach to curriculum design, beginning with a set of skills that define a particular career role. A further goal was to evaluate the extent to which SFIA facilitates stakeholder interaction, such that academic programs can better identify industry needs while preparing graduates for the intended career role. The paper also evaluates the extent to which SFIA informs the identification of authentic forms of assessment and the skills and levels of autonomy and responsibility required by entry-level and Masters graduate ICT positions. Processes and practices for ICT curriculum design and management are recommended based on findings arising from this research. Although this research was conducted in an Australian context, findings suggest that there is value in using SFIA for ICT curriculum design and management, even in those jurisdictions where it is not required for accreditation or professional certification purposes
Deformation Characteristics and Work-hardening Behaviour of some High Strength Manganese Steels
A study has been made on a new type of wear
resistant/high strength iron-manganse-molybdenum steel. This
study includes the influence of composition and heat treatment
on the mechanical properties. The exceptional work-hardening
rate is due to strain-induced formation of lath martensite
which itself also takes part in the work-hardening process.
The influence of higher molybdenum contents was evident in
preventing brittleness of the solution treated steels. An
optimum composition range for this type of steel is indicated
The Regulation of Aggrecanase ADAMTS-4 Expression in Human Achilles Tendon and tendon-Derived Cells
Several members of the ADAMTS (A Disintegrin And Metalloproteinase with ThromboSpondin motifs) family have been identified as aggrecanases, whose substrates include versican, the principal large proteoglycan in the tendon extracellular matrix. We have characterized the expression of ADAMTS-4 in human Achilles tendon and tendon-derived cells. ADAMTS-4 mRNA levels were higher in ruptured tendon compared with normal tendon or chronic painful tendinopathy. In tissue extracts probed by Western blotting, mature ADAMTS-4 (68 kDa) was detected only in ruptured tendons, while processed ADAMTS-4 (53 kDa) was detected also in chronic painful tendinopathy and in normal tendon. In cultured Achilles tendon cells, transforming growth factor-Ăź (TGF-Ăź) stimulated ADAMTS-4 mRNA expression (typically 20-fold after 24 h), while interleukin-1 induced a smaller, shorter-term stimulation which synergised markedly with that induced by TGF-Ăź. Increased levels of immunoreactive proteins consistent with mature and processed forms of ADAMTS-4 were detected in TGF-Ăź-stimulated cells. ADAMTS-4 mRNA was expressed at higher levels by tendon cells in collagen gels than in monolayer cultures. In contrast, the expression of ADAMTS-1 and -5 mRNA was lower in collagen gels compared with monolayers, and these mRNA showed smaller or opposite responses to growth factors and cytokines compared with that of ADAMTS-4 mRNA. We conclude that both ADAMTS-4 mRNA and ADAMTS-4 protein processing may be differentially regulated in normal and damaged tendons and that both the matrix environment and growth factors such as TGF-Ăź are potentially important factors controlling ADAMTS aggrecanase activities in tendon pathology
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Extreme morning chronotypes are often familial and not exceedingly rare: the estimated prevalence of advanced sleep phase, familial advanced sleep phase, and advanced sleep-wake phase disorder in a sleep clinic population.
Study objectivesReport the first prevalence estimates of advanced sleep phase (ASP), familial advanced sleep phase (FASP), and advanced sleep-wake phase disorder (ASWPD). This can guide clinicians on the utility of screening for extreme chronotypes both for clinical decision-making and to flag prospective participants in the study of the genetics and biology of FASP.MethodsData on morning or evening sleep schedule preference (chronotype) were collected from 2422 new patients presenting to a North American sleep center over 9.8 years. FASP was determined using a severity criterion that has previously identified dominant circadian mutations in humans. All patients were personally seen and evaluated by one of the authors (C.R.J.).ResultsOur results demonstrate an ASP prevalence of 0.33%, an FASP prevalence of 0.21%, and an ASWPD prevalence of at least 0.04%. Most cases of young-onset ASP were familial.ConclusionsAmong patients presenting to a sleep clinic, conservatively 1 out of every 300 patients will have ASP, 1 out of every 475 will have FASP, and 1 out of every 2500 will have ASWPD. This supports obtaining a routine circadian history and, for those with extreme chronotypes, obtaining a family history of circadian preference. This can optimize treatment for evening sleepiness and early morning awakening and lead to additional circadian gene discovery. We hope these findings will lead to improved treatment options for a wide range of sleep and medical disorders in the future
Three years in a doctoral cohort: A survivalist's guide
This narrative study examines the relationships and experiences of twelve members of a doctoral cohort in the field of educational administration. Although many studies on the success of the cohort model have been conducted, this study offers an uncommon viewpoint as the researcher is himself a member of the cohort from the first day of coursework through the last day, three years later. As such, one-twelfth of the relationships and experiences within the cohort are understood and narrated through the first-person experiences of the researcher, with the other eleven members of the cohort being given equal time and equal voice in second-person narration. The study was completed at the end of a three-year period of coursework and individuals of the cohort, the original twelve that both started and finished their degrees as part of the cohort, were interviewed individually as well as in a focus group regarding their memories, experiences, and relationships. Social network theory was used as the theoretical framing for the analysis, which surfaced three themes: the process of joining the cohort, the support cohort members provided one another, and the experiences and relationships that developed from being a member of a three-year doctoral cohort. Conclusions are drawn involving the success, as defined by the completion of the coursework, of the cohort being tied directly to the relationships that were formed by cohort members. Implications involving the establishment of relationships among cohort members are shown, and other recommendations for further studies are given
The Importance of who and what in Interruption Management: Empirical Evidence from a Cell Phone Use Study
Interruption management in technology mediated communication is a key concern in collaborative work and social environments. Previous empirical and theoretical work in predicting interruptibility predominantly focuses on interruptee’s local context namely identifying cognitively and socially intruding contexts such as mental work load levels, activity, place of activity. They largely ignore the relational context namely “who” the interruption is from or “what” it is about. This paper addresses this issue by systematically investigating the use of the various contextual factors in interruption management practices of everyday cell phone use. Analysis of 1201 incoming calls from our experience sampling method study of cell phone use, shows that “who” is calling is used most of the time (87.4%) by individuals to make deliberate call handling decisions (N=834), in contrast to the interruptee’s current local social (34.9%) or cognitive (43%) contexts. We present implications of these findings for the design of interruption management tools for communication media
Current and Future Treatment of Mucopolysaccharidosis (MPS) Type II: Is Brain-Targeted Stem Cell Gene Therapy the Solution for This Devastating Disorder?
Mucopolysaccharidosis type II (Hunter Syndrome) is a rare, x-linked recessive, progressive, multi-system, lysosomal storage disease caused by the deficiency of iduronate-2-sulfatase (IDS), which leads to the pathological storage of glycosaminoglycans in nearly all cell types, tissues and organs. The condition is clinically heterogeneous, and most patients present with a progressive, multi-system disease in their early years. This article outlines the pathology of the disorder and current treatment strategies, including a detailed review of haematopoietic stem cell transplant outcomes for MPSII. We then discuss haematopoietic stem cell gene therapy and how this can be employed for treatment of the disorder. We consider how preclinical innovations, including novel brain-targeted techniques, can be incorporated into stem cell gene therapy approaches to mitigate the neuropathological consequences of the condition
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