386 research outputs found
Reply to: Terry, J. and Goff, J. comment on âLate Cenozoic sea level and the rise of modern rimmed atollsâ by Toomey et al. (2016), Palaeogeography, Palaeoclimatology, Palaeoecology 451: 73â83
This paper is not subject to U.S. copyright. The definitive version was published in Palaeogeography, Palaeoclimatology, Palaeoecology 469 (2017): 159-160, doi:10.1016/j.palaeo.2016.11.028
Late Cenozoic sea level and the rise of modern rimmed atolls
This paper is not subject to U.S. copyright. The definitive version was published in Palaeogeography, Palaeoclimatology, Palaeoecology 451 (2016): 73-83, doi:10.1016/j.palaeo.2016.03.018.Sea-level records from atolls, potentially spanning the Cenozoic, have been largely overlooked, in part because the processes that control atoll form (reef accretion, carbonate dissolution, sediment transport, vertical motion) are complex and, for many islands, unconstrained on million-year timescales. Here we combine existing observations of atoll morphology and corelog stratigraphy from Enewetak Atoll with a numerical model to (1) constrain the relative rates of subsidence, dissolution and sedimentation that have shaped modern Pacific atolls and (2) construct a record of sea level over the past 8.5 million years. Both the stratigraphy from Enewetak Atoll (constrained by a subsidence rate of ~ 20 m/Myr) and our numerical modeling results suggest that low sea levels (50â125 m below present), and presumably bi-polar glaciations, occurred throughout much of the late Miocene, preceding the warmer climate of the Pliocene, when sea level was higher than present. Carbonate dissolution through the subsequent sea-level fall that accompanied the onset of large glacial cycles in the late Pliocene, along with rapid highstand constructional reef growth, likely drove development of the rimmed atoll morphology we see today.Support for this work was provided through a Jackson School Distinguished Postdoctoral Fellowship to Michael Toomey
Geometry and Adhesion of Extracellular Domains of DC-SIGNR Neck Length Variants Analyzed by ForceâDistance Measurements
Force-distance measurements have been used to examine differences in the interaction of the dendritic cell glycan-binding receptor DC-SIGN and the closely related endothelial cell receptor DC-SIGNR (L-SIGN) with membranes bearing glycan ligands. The results demonstrate that upon binding to membrane-anchored ligand, DC-SIGNR undergoes a conformational change similar to that previously observed for DC-SIGN. The results also validate a model for the extracellular domain of DC-SIGNR derived from crystallographic studies. Force measurements were performed with DC-SIGNR variants that differ in the length of the neck that result from genetic polymorphisms, which encode different numbers of the 23-amino acid repeat sequences that constitute the neck. The findings are consistent with an elongated, relatively rigid structure of the neck repeat observed in crystals. In addition, differences in the lengths of DC-SIGN and DC-SIGNR extracellular domains with equivalent numbers of neck repeats support a model in which the different dispositions of the carbohydrate-recognition domains in DC-SIGN and DC-SIGNR result from variations in the sequences of the necks
Educating Future Nursing Scientists: Recommendations for Integrating Omics Content in PhD Programs
Preparing the next generation of nursing scientists to conduct high-impact, competitive, sustainable, innovative, and interdisciplinary programs of research requires that the curricula for PhD programs keep pace with emerging areas of knowledge and health care/biomedical science. A field of inquiry that holds great potential to influence our understanding of the underlying biology and mechanisms of health and disease is omics. For the purpose of this article, omics refers to genomics, transcriptomics, proteomics, epigenomics, exposomics, microbiomics, and metabolomics. Traditionally, most PhD programs in schools of nursing do not incorporate this content into their core curricula. As part of the Council for the Advancement of Nursing Science\u27s Idea Festival for Nursing Science Education, a work group charged with addressing omics preparation for the next generation of nursing scientists was convened. The purpose of this article is to describe key findings and recommendations from the work group that unanimously and enthusiastically support the incorporation of omics content into the curricula of PhD programs in nursing. The work group also calls to action faculty in schools of nursing to develop strategies to enable students needing immersion in omics science and methods to execute their research goals
Norovirus epidemiology in Africa : a review
Norovirus (NoV) is recognised as a leading cause of gastroenteritis worldwide across all
age groups. The prevalence and diversity of NoVs in many African countries is still
unknown, although early sero-prevalence studies indicated widespread early infection.
Reports on NoVs in Africa vary widely in terms of study duration, population groups and
size, inclusion of asymptomatic controls, as well as genotyping information. This review provides
an estimate of NoV prevalence and distribution of genotypes of NoVs in Africa. Inclusion
criteria for the review were study duration of at least 6 months, population size of >50
and diagnosis by RT-PCR. As regions used for genotyping varied, or genotyping was not
always performed, this was not considered as an inclusion criteria. A literature search containing
the terms norovirus+Africa yielded 74 publications. Of these 19 studies from 14 out
of the 54 countries in Africa met the inclusion criteria. Data from studies not meeting the
inclusion criteria, based on sample size or short duration, were included as discussion
points. The majority of studies published focused on children, under five years of age, hospitalised
with acute gastroenteritis. The mean overall prevalence was 13.5% (range 0.8â
25.5%) in children with gastroenteritis and 9.7% (range 7â31%) in asymptomatic controls,
where tested. NoV GII.4 was the predominant genotype identified in most of the studies that
presented genotyping data. Other prevalent genotypes detected included GII.3 and GII.6.
In conclusion, NoV is a common pathogen in children with diarrhoea in Africa, with considerable
carriage in asymptomatic children. There is however, a paucity of data on NoV infection
in adults.http://www.plosone.orgam2016Medical Microbiolog
Transgenic increases in seed oil content are associated with the differential expression of novel Brassica-specific transcripts
<p>Abstract</p> <p>Background</p> <p>Seed oil accumulates primarily as triacylglycerol (TAG). While the biochemical pathway for TAG biosynthesis is known, its regulation remains unclear. Previous research identified microsomal diacylglycerol acyltransferase 1 (DGAT1, EC 2.3.1.20) as controlling a rate-limiting step in the TAG biosynthesis pathway. Of note, overexpression of <it>DGAT1 </it>results in substantial increases in oil content and seed size. To further analyze the global consequences of manipulating <it>DGAT1 </it>levels during seed development, a concerted transcriptome and metabolome analysis of transgenic <it>B. napus </it>prototypes was performed.</p> <p>Results</p> <p>Using a targeted <it>Brassica </it>cDNA microarray, about 200 genes were differentially expressed in two independent transgenic lines analyzed. Interestingly, 24â33% of the targets showing significant changes have no matching gene in <it>Arabidopsis </it>although these represent only 5% of the targets on the microarray. Further analysis of some of these novel transcripts indicated that several are inducible by ABA in microspore-derived embryos. Of the 200 <it>Arabidopsis </it>genes implicated in lipid biology present on the microarray, 36 were found to be differentially regulated in DGAT transgenic lines. Furthermore, kinetic reverse transcriptase Polymerase Chain Reaction (k-PCR) analysis revealed up-regulation of genes encoding enzymes of the Kennedy pathway involved in assembly of TAGs. Hormone profiling indicated that levels of auxins and cytokinins varied between transgenic lines and untransformed controls, while differences in the pool sizes of ABA and catabolites were only observed at later stages of development.</p> <p>Conclusion</p> <p>Our results indicate that the increased TAG accumulation observed in transgenic <it>DGAT1 </it>plants is associated with modest transcriptional and hormonal changes during seed development that are not limited to the TAG biosynthesis pathway. These might be associated with feedback or feed-forward effects due to altered levels of DGAT1 activity. The fact that a large fraction of significant amplicons have no matching genes in <it>Arabidopsis </it>compromised our ability to draw concrete inferences from the data at this stage, but has led to the identification of novel genes of potential interest.</p
Feasibility study to assess the impact of a lifestyle intervention (âLivingWELLâ) in people having an assessment of their family history of colorectal or breast cancer
Objectives To assess the feasibility of delivering and evaluating a weight management (WM) programme for overweight patients with a family history (FH) of breast cancer (BC) or colorectal cancer (CRC). Study design A two-arm (intervention vs usual care) randomised controlled trial. Setting National Health Service (NHS) Tayside and NHS Grampian. Participants People with a FH of BC or CRC agedâ„18 years and body mass index of â„25 kg/m2 referred to NHS genetic services. Intervention Participants were randomised to a control (lifestyle booklet) or 12-week intervention arm where they were given one face-to-face counselling session, four telephone consultations and web-based support. A goal of 5% reduction in body weight was set, and a personalised diet and physical activity (PA) programme was provided. Behavioural change techniques (motivational interviewing, action and coping plans and implementation intentions) were used. Primary outcome Feasibility measures: recruitment, programme implementation, fidelity measures, achieved measurements and retention, participant satisfaction assessed by questionnaire and qualitative interviews. Secondary outcomes Measured changes in weight and PA and reported diet and psychosocial measures between baseline and 12-week follow-up. Results Of 480 patients approached, 196 (41%) expressed interest in the study, and of those, 78 (40%) patients were randomised. Implementation of the programme was challenging within the time allotted and fidelity to the intervention modest (62%). Qualitative findings indicated the programme was well received. Questionnaires and anthropometric data were completed by >98%. Accelerometer data were attained by 84% and 54% at baseline and follow-up, respectively. Retention at 12 weeks was 76%. Overall, 36% of the intervention group (vs 0% in control) achieved 5% weight loss. Favourable increases in PA and reduction in dietary fat were also reported. Conclusions A lifestyle programme for people with a family history of cancer is feasible to conduct and acceptable to participants, and indicative results suggest favourable outcomes. Trial registration number ISRCTN13123470; Pre-results
Pretreatment dietary intake is associated with tumor suppressor DNA methylation in head and neck squamous cell carcinomas
Diet is associated with cancer prognosis, including head and neck cancer (HNC), and has been hypothesized to influence epigenetic state by determining the availability of functional groups involved in the modification of DNA and histone proteins. The goal of this study was to describe the association between pretreatment diet and HNC tumor DNA methylation. Information on usual pretreatment food and nutrient intake was estimated via food frequency questionnaire (FFQ) on 49 HNC cases. Tumor DNA methylation patterns were assessed using the Illumina Goldengate Methylation Cancer Panel. First, a methylation score, the sum of individual hypermethylated tumor suppressor associated CpG sites, was calculated and associated with dietary intake of micronutrients involved in one-carbon metabolism and antioxidant activity, and food groups abundant in these nutrients. Second, gene specific analyses using linear modeling with empirical Bayesian variance estimation were conducted to identify if methylation at individual CpG sites was associated with diet. All models were controlled for age, sex, smoking, alcohol and HPV status. Individuals reporting in the highest quartile of folate, vitamin B12 and vitamin A intake, compared with those in the lowest quartile, showed significantly less tumor suppressor gene methylation, as did patients reporting the highest cruciferous vegetable intake. Gene specific analyses identified differential associations between DNA methylation and vitamin B12 and vitamin A intake when stratifying by HPV status. These preliminary results suggest that intake of folate, vitamin A and vitamin B12 may be associated with the tumor DNA methylation profile in HNC and enhance tumor suppression
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