5,534 research outputs found
Triplet Irradiance Measurements
Cloud speed and direction govern the dynamic nature of irradiance, and hence the electrical output of PV panels and arrays. For example, ramp rates are directly proportional to the cloud speed and related to the coincidence of cloud direction and array orientation. In this work, we demonstrate that cloud dynamics can be determined using a triplet of silicon irradiance sensors logged at high frequency. Using cross-correlation, cloud speed and direction are calculated from the time shifts of cloud edges detected from sensor pairs. Data was initially recorded for 5 months from March 2016, near Leeds, UK. Further data will be recorded in 2018, near Kampala, Uganda. From the 2016 data, minimum cloud speeds of 4 ms-1 and a maximum of 40 ms-1 were obtained while dominant direction was found to be from the west-northwest. Comparison was then made to hourly wind speed and direction data recorded at 10 m above the ground level from the Bingley SAMOS weather station which is located 4 km away from the triplet of irradiance sensors. Cloud speed is invariably higher than the 10 m wind speed, on account friction between air and the earth’s surface. Nevertheless, we report a strong linear relationship between cloud speed and 10 m wind speed, with a correlation coefficient, R, of 0.9. Regarding comparison of direction, a deflection of 22.50 in the cloud direction clockwise of 10 m wind direction was observed as the dominant ground level wind direction was found to be from the west, while the dominant direction of the clouds was found to be from the west-northwest. Ramp rates were determined and compared with 10 m wind speeds. A low to moderate positive correlation were observed with a minimum and maximum correlation coefficient, R, of 0.2095 and 0.4274 in June and April respectively. These correlations are understood to have been diminished because of noise and solar irradiance reflected and focused onto the sensors by various cloud sides. This work demonstrates that both triplets of irradiance sensors and ground level wind data are useful and low-cost methods for predicting the likely frequency and magnitude of ramp rates of PV arrays
Deletions of the derivative chromosome 9 occur at the time of the Philadelphia translocation and provide a powerful and independent prognostic indicator in chronic myeloid leukemia
Chronic myeloid leukemia (CML) is characterized by formation of the BCR-ABL fusion gene, usually as a consequence of the Philadelphia (Ph) translocation between chromosomes 9 and 22. Large deletions on the derivative chromosome 9 have recently been reported, but it was unclear whether deletions arose during disease progression or at the time of the Ph translocation. Fluorescence in situ hybridization (FISH) analysis was used to assess the deletion status of 253 patients with CML. The strength of deletion status as a prognostic indicator was then compared to the Sokal and Hasford scoring systems. The frequency of deletions was similar at diagnosis and after disease progression but was significantly increased in patients with variant Ph translocations. In patients with a deletion, all Ph+ metaphases carried the deletion. The median survival of patients with and without deletions was 38 months and 88 months, respectively (P = .0001). By contrast the survival difference between Sokal or Hasford high-risk and non-high-risk patients was of only borderline significance (P = .057 and P = .034). The results indicate that deletions occur at the time of the Ph translocation. An apparently simple reciprocal translocation may therefore result in considerable genetic heterogeneity ab initio, a concept that is likely to apply to other malignancies associated with translocations. Deletion status is also a powerful and independent prognostic factor for patients with CML. The prognostic significance of deletion status should now be studied prospectively and, if confirmed, should be incorporated into management decisions and the analysis of clinical trials. (C) 2001 by The American Society of Hematology
Converting systematic reviews to Cochrane format: a cross-sectional survey of Australian authors of systematic reviews
BACKGROUND: Despite the growing reputation and subject coverage of the Cochrane Database of Systematic Reviews, many systematic reviews continue to be published solely in paper-based health care journals. This study was designed to determine why authors choose to publish their systematic reviews outside of the Cochrane Collaboration and if they might be interested in converting their reviews to Cochrane format for publication in the Cochrane Database of Systematic Reviews. METHODS: Cross-sectional survey of Australian primary authors of systematic reviews not published on the Cochrane Database of Systematic Reviews identified from the Database of Abstracts of Reviews of Effectiveness. RESULTS: We identified 88 systematic reviews from the Database of Abstracts of Reviews of Effectiveness with an Australian as the primary author. We surveyed 52 authors for whom valid contact information was available. The response rate was 88 per cent (46/52). Ten authors replied without completing the survey, leaving 36 valid surveys for analysis. The most frequently cited reasons for not undertaking a Cochrane review were: lack of time (78%), the need to undergo specific Cochrane training (46%), unwillingness to update reviews (36%), difficulties with the Cochrane process (26%) and the review topic already registered with the Cochrane Collaboration (21%). (Percentages based on completed responses to individual questions.) Nearly half the respondents would consider converting their review to Cochrane format. Dedicated time emerged as the most important factor in facilitating the potential conversion process. Other factors included navigating the Cochrane system, assistance with updating and financial support. Eighty-six per cent were willing to have their review converted to Cochrane format by another author. CONCLUSION: Time required to complete a Cochrane review and the need for specific training are the primary reasons why some authors publish systematic reviews outside of the Cochrane Collaboration. Encouragingly, almost half of the authors would consider converting their review to Cochrane format. Based on the current number of reviews in the Database of Abstracts of Reviews of Effectiveness, this could result in more than 700 additional Cochrane reviews. Ways of supporting these authors and how to provide dedicated time to convert systematic reviews needs further consideration
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JAK2V617F mediates resistance to DNA damage-induced apoptosis by modulating FOXO3A localization and Bcl-xL deamidation.
The JAK2V617F mutation is found in most patients with a myeloproliferative neoplasm (MPN). This gain-of-function mutation dysregulates cytokine signaling and is associated with increased accumulation of DNA damage, a process likely to drive disease evolution. JAK2V617F inhibits NHE-1 upregulation in response to DNA damage and consequently represses Bcl-xL deamidation and apoptosis, thus giving rise to inappropriate cell survival. However, the mechanism whereby NHE-1 expression is inhibited by JAK2V617F is unknown. In this study, we demonstrate that the accumulation of reactive oxygen species (ROS) in cells expressing JAK2V617F compromises the NHE-1/Bcl-xL deamidation pathway by repressing NHE-1 upregulation in response to DNA damage. In JAK2V617F-positive cells, increased ROS levels results from aberrant PI3K signaling, which decreases nuclear localization of FOXO3A and decreases catalase expression. Furthermore, when compared with autologous control erythroblasts, clonally derived JAK2V617F-positive erythroblasts from MPN patients displayed increased ROS levels and reduced nuclear FOXO3A. However, in hematopoietic stem cells (HSCs), FOXO3A is largely localized within the nuclei despite the presence of JAK2V617F mutation, suggesting that JAK2-FOXO signaling has a different effect on progenitors compared with stem cells. Inactivation of FOXO proteins and elevation of intracellular ROS are characteristics common to many cancers, and hence these findings are likely to be of relevance beyond the MPN field.Work in the Green lab is supported by Leukemia and Lymphoma
Research, Cancer Research UK, the Kay Kendall Leukaemia Fund, the NIHR
Cambridge Biomedical Research Centre, the Cambridge Experimental Cancer
Medicine Centre, and the Leukemia & Lymphoma Society of America. DGK was
supported by a postdoctoral fellowship from the Canadian Institutes of Health
Research (Ottawa, ON), and a Lady Tata Memorial Trust International Award for
Research in Leukaemia (London, UK). HJP was supported by a postdoctoral
fellowship from the Human Frontier Science Program.This is the accepted manuscript. The final version is available at http://www.nature.com/onc/journal/vaop/ncurrent/full/onc2015285a.html
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Mbd3/NuRD controls lymphoid cell fate and inhibits tumorigenesis by repressing a B cell transcriptional program
Differentiation of lineage-committed cells from multipotent progenitors requires establishment of accessible chromatin at lineage-specific transcriptional enhancers and promoters, which is mediated by pioneer transcription factors that recruit activating chromatin remodeling complexes. Here we show that the Mbd3/NuRD chromatin remodeling complex opposes this transcriptional pioneering during B cell programming of multipotent lymphoid progenitors by restricting chromatin accessibility at B cell enhancers and promoters. Mbd3/NuRD-deficient lymphoid progenitors therefore prematurely activate a B cell transcriptional program and are biased towards overproduction of pro-B cells at the expense of T cell progenitors. The striking reduction in early thymic T cell progenitors results in compensatory hyperproliferation of immature thymocytes and development of T cell lymphoma. Our results reveal that Mbd3/NuRD can regulate multilineage differentiation by constraining the activation of dormant lineage-specific enhancers and promoters. In this way, Mbd3/NuRD protects the multipotency of lymphoid progenitors, preventing B cell-programming transcription factors from prematurely enacting lineage commitment. Mbd3/NuRD therefore controls the fate of lymphoid progenitors, ensuring appropriate production of lineage-committed progeny and suppressing tumour formation.F.C. was supported by an EMBO long-term fellowship (1305-2015 and Marie Curie Actions LTFCOFUND2013/GA-2013-609409). Work in the Green lab is supported Cancer Research UK (grants refs. C1163/A12765 and C1163/A12526), Bloodwise (grant ref. 13003), and core support grants by the Wellcome Trust to the Cambridge Institute for Medical Research (100140/Z/12/Z) and Wellcome Trust-MRC Cambridge Stem Cell Institute (097922/Z/11/Z)
Water dispersible microbicidal cellulose acetate phthalate film
BACKGROUND: Cellulose acetate phthalate (CAP) has been used for several decades in the pharmaceutical industry for enteric film coating of oral tablets and capsules. Micronized CAP, available commercially as "Aquateric" and containing additional ingredients required for micronization, used for tablet coating from water dispersions, was shown to adsorb and inactivate the human immunodeficiency virus (HIV-1), herpesviruses (HSV) and other sexually transmitted disease (STD) pathogens. Earlier studies indicate that a gel formulation of micronized CAP has a potential as a topical microbicide for prevention of STDs including the acquired immunodeficiency syndrome (AIDS). The objective of endeavors described here was to develop a water dispersible CAP film amenable to inexpensive industrial mass production. METHODS: CAP and hydroxypropyl cellulose (HPC) were dissolved in different organic solvent mixtures, poured into dishes, and the solvents evaporated. Graded quantities of a resulting selected film were mixed for 5 min at 37°C with HIV-1, HSV and other STD pathogens, respectively. Residual infectivity of the treated viruses and bacteria was determined. RESULTS: The prerequisites for producing CAP films which are soft, flexible and dispersible in water, resulting in smooth gels, are combining CAP with HPC (other cellulose derivatives are unsuitable), and casting from organic solvent mixtures containing ≈50 to ≈65% ethanol (EtOH). The films are ≈100 µ thick and have a textured surface with alternating protrusions and depressions revealed by scanning electron microscopy. The films, before complete conversion into a gel, rapidly inactivated HIV-1 and HSV and reduced the infectivity of non-viral STD pathogens >1,000-fold. CONCLUSIONS: Soft pliable CAP-HPC composite films can be generated by casting from organic solvent mixtures containing EtOH. The films rapidly reduce the infectivity of several STD pathogens, including HIV-1. They are converted into gels and thus do not have to be removed following application and use. In addition to their potential as topical microbicides, the films have promise for mucosal delivery of pharmaceuticals other than CAP
A wide-area GMRT 610-MHz survey of ELAIS N1 field
In this paper we present a wide-area 610 MHz survey of the ELAIS\,N1 field
with the GMRT, covering an area of 12.8 deg at a resolution of 6 arcsec and
with an rms noise of Jy beam. This is equivalent to Jy beam rms noise at 1.4 GHz for a spectral index of .
The primary goal of the survey was to study the polarised sky at sub-mJy flux
densities at GHz frequencies. In addition, a range of other science goals,
such as investigations in to the nature of the low-frequency Jy source
populations and alignments of radio jets. A total of 6,400 sources were found
in this region, the vast majority of them compact. The sample jointly detected
by GMRT at 610 MHz and by VLA FIRST at 1.4\,GHz has a median spectral index of
and a median 610 MHz flux density of 4.5 mJy. This region has
a wealth of ancillary data which is useful to characterize the detected
sources. The multi-wavelength cross matching resulted optical/IR counterparts
to per~cent of the radio sources, with a significant fraction having
at least photometric redshift. Due to the improved sensitivity of this survey
over preceding ones, we have discovered six giant radio sources (GRS), with
three of them at or higher. This implies that the population of GRS
may be more abundant and common than known to date and if true this has
implications for the luminosity function and the evolution of radio sources. We
have also identified several candidate extended relic sources
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