341 research outputs found
An original interferometric study of NGC 1068 with VISIR BURST mode images
We present 12.8 microns images of the core of NGC 1068 obtained with the
BURST mode of the VLT/VISIR. We trace structures under the diffraction limit of
one UT and we investigate the link between dust in the vicinity of the central
engine of NGC 1068, recently resolved by interferometry with MIDI, and more
extended structures. This step is mandatory for a multi-scale understanding of
the sources of mid-infrared emission in AGNs. A speckle processing of VISIR
BURST mode images was performed to extract very low spatial-frequency
visibilities, first considering the full field of VISIR BURST mode images and
then limiting it to the mask used for the acquisition of MIDI data. Extracted
visibilities are reproduced with a multi-component model. We identify two major
sources of emission: one compact < 85 mas, associated with the dusty torus, and
an elliptical one, (< 140) mas x 1187 mas at P.A.=-4 degrees from N to E. This
is consistent with previous deconvolution processes. The combination with MIDI
data reveals the close environment of the dusty torus to contribute to about 83
percent of the MIR flux seen by MIDI. This strong contribution has to be
considered in modeling long baseline interferometric data. It must be related
to the NS elongated component which is thought to originate from individually
unresolved dusty clouds and is located inside the ionization cone. Low
temperatures of the dusty torus are not challenged, emphasizing the scenarios
of clumpy torus.Comment: 10 pages, 7 figures, accepted for publication in A&
Recommended from our members
Proprietary, standard, and government-supported nuclear data bases
On the effective shear speed in 2D phononic crystals
The quasistatic limit of the antiplane shear-wave speed ('effective speed')
in 2D periodic lattices is studied. Two new closed-form estimates of
are derived by employing two different analytical approaches. The first
proceeds from a standard background of the plane wave expansion (PWE). The
second is a new approach, which resides in -space and centers on
the monodromy matrix (MM) introduced in the 2D case as the multiplicative
integral, taken in one coordinate, of a matrix with components being the
operators with respect to the other coordinate. On the numerical side, an
efficient PWE-based scheme for computing is proposed and implemented. The
analytical and numerical findings are applied to several examples of 2D square
lattices with two and three high-contrast components, for which the new PWE and
MM estimates are compared with the numerical data and with some known
approximations. It is demonstrated that the PWE estimate is most efficient in
the case of densely packed stiff inclusions, especially when they form a
symmetric lattice, while in general it is the MM estimate that provides the
best overall fitting accuracy.Comment: 13 pages, 9 figure
Marker-Assisted Pyramiding of Blast-Resistance Genes in a japonica Elite Rice Cultivar through Forward and Background Selection
Rice blast, caused by Pyricularia oryzae, is one of the main rice diseases worldwide. The
pyramiding of blast-resistance (Pi) genes, coupled to Marker-Assisted BackCrossing (MABC), provides
broad-spectrum and potentially durable resistance while limiting the donor genome in the
background of an elite cultivar. In this work, MABC coupled to foreground and background selections
based on KASP marker assays has been applied to introgress four Pi genes (Piz, Pib, Pita, and
Pik) in a renowned japonica Italian rice variety, highly susceptible to blast. Molecular analyses on the
backcross (BC) lines highlighted the presence of an additional blast-resistance gene, the Pita-linked
Pita2/Ptr gene, therefore increasing the number of blast-resistance introgressed genes to five. The
recurrent genome was recovered up to 95.65%. Several lines carrying four (including Pita2) Pi genes
with high recovery percentage levels were also obtained. Phenotypic evaluations confirmed the
effectiveness of the pyramided lines against multivirulent strains, which also had broad patterns
of resistance in comparison to those expected based on the pyramided Pi genes. The developed
blast-resistant japonica lines represent useful donors of multiple blast-resistance genes for future
rice-breeding programs related to the japonica group
Ovarian-Adnexal Reporting Data System Magnetic Resonance Imaging (O-RADS MRI) score for risk stratification of sonographically indeterminate adnexal masses.
Importance: Approximately one-quarter of adnexal masses detected at ultrasonography are indeterminate for benignity or malignancy, posing a substantial clinical dilemma. Objective: To validate the accuracy of a 5-point Ovarian-Adnexal Reporting Data System Magnetic Resonance Imaging (O-RADS MRI) score for risk stratification of adnexal masses. Design, Setting, and Participants: This multicenter cohort study was conducted between March 1, 2013, and March 31, 2016. Among patients undergoing expectant management, 2-year follow-up data were completed by March 31, 2018. A routine pelvic MRI was performed among consecutive patients referred to characterize a sonographically indeterminate adnexal mass according to routine diagnostic practice at 15 referral centers. The MRI score was prospectively applied by 2 onsite readers and by 1 reader masked to clinical and ultrasonographic data. Data analysis was conducted between April and November 2018. Main Outcomes and Measures: The primary end point was the joint analysis of true-negative and false-negative rates according to the MRI score compared with the reference standard (ie, histology or 2-year follow-up). Results: A total of 1340 women (mean [range] age, 49 [18-96] years) were enrolled. Of 1194 evaluable women, 1130 (94.6%) had a pelvic mass on MRI with a reference standard (surgery, 768 [67.9%]; 2-year follow-up, 362 [32.1%]). A total of 203 patients (18.0%) had at least 1 malignant adnexal or nonadnexal pelvic mass. No invasive cancer was assigned a score of 2. Positive likelihood ratios were 0.01 for score 2, 0.27 for score 3, 4.42 for score 4, and 38.81 for score 5. Area under the receiver operating characteristic curve was 0.961 (95% CI, 0.948-0.971) among experienced readers, with a sensitivity of 0.93 (95% CI, 0.89-0.96; 189 of 203 patients) and a specificity of 0.91 (95% CI, 0.89-0.93; 848 of 927 patients). There was good interrater agreement among both experienced and junior readers (κ = 0.784; 95% CI, 0.743-0824). Of 580 of 1130 women (51.3%) with a mass on MRI and no specific gynecological symptoms, 362 (62.4%) underwent surgery. Of them, 244 (67.4%) had benign lesions and a score of 3 or less. The MRI score correctly reclassified the mass origin as nonadnexal with a sensitivity of 0.99 (95% CI, 0.98-0.99; 1360 of 1372 patients) and a specificity of 0.78 (95% CI, 0.71-0.85; 102 of 130 patients). Conclusions and Relevance: In this study, the O-RADS MRI score was accurate when stratifying the risk of malignancy in adnexal masses
Cardiosphere-derived cells suppress allogeneic lymphocytes by production of PGE2 acting via the EP4 receptor
derived cells (CDCs) are a cardiac progenitor cell population, which have been shown to possess cardiac regenerative properties and can improve heart function in a variety of cardiac diseases. Studies in large animal models have predominantly focussed on using autologous cells for safety, however allogeneic cell banks would allow for a practical, cost-effective and efficient use in a clinical setting. The aim of this work was to determine the immunomodulatory status of these cells using CDCs and lymphocytes from 5 dogs. CDCs expressed MHC I but not MHC II molecules and in mixed lymphocyte reactions demonstrated a lack of lymphocyte proliferation in response to MHC-mismatched CDCs. Furthermore, MHC-mismatched CDCs suppressed lymphocyte proliferation and activation in response to Concanavalin A. Transwell experiments demonstrated that this was predominantly due
to direct cell-cell contact in addition to soluble mediators whereby CDCs produced high levels of PGE2
under inflammatory conditions. This led to down-regulation of CD25 expression on lymphocytes via the
EP4 receptor. Blocking prostaglandin synthesis restored both, proliferation and activation (measured via CD25 expression) of stimulated lymphocytes. We demonstrated for the first time in a large animal model that CDCs inhibit proliferation in allo-reactive lymphocytes and have potent immunosuppressive activity mediated via PGE2
Multilevel factors are associated with immunosuppressant nonadherence in heart transplant recipients: The international BRIGHT study
Factors at the level of family/healthcare worker, organization, and system are neglected in medication nonadherence research in heart transplantation (HTx). The 4-continent, 11-country cross-sectional Building Research Initiative Group: Chronic Illness Management and Adherence in Transplantation (BRIGHT) study used multistaged sampling to examine 36 HTx centers, including 36 HTx directors, 100 clinicians, and 1397 patients. Nonadherence to immunosuppressants\u2014defined as any deviation in taking or timing adherence and/or dose reduction\u2014was assessed using the Basel Assessment of Adherence to Immunosuppressive Medications Scale \ua9 (BAASIS \ua9 ) interview. Guided by the Integrative Model of Behavioral Prediction and Bronfenbrenner's ecological model, we analyzed factors at these multiple levels using sequential logistic regression analysis (6 blocks). The nonadherence prevalence was 34.1%. Six multilevel factors were associated independently (either positively or negatively) with nonadherence: patient level: barriers to taking immunosuppressants (odds ratio [OR]: 11.48); smoking (OR: 2.19); family/healthcare provider level: frequency of having someone to help patients read health-related materials (OR: 0.85); organization level: clinicians reporting nonadherent patients were targeted with adherence interventions (OR: 0.66); pickup of medications at physician's office (OR: 2.31); and policy level: monthly out-of-pocket costs for medication (OR: 1.16). Factors associated with nonadherence are evident at multiple levels. Improving medication nonadherence requires addressing not only the patient, but also family/healthcare provider, organization, and policy levels
Cell delivery systems using alginate : carrageenan hydrogel beads and fibers for regenerative medicine applications
The present work was focused on the development and characterization of new hydrogel systems based on natural
origin polymers, namely, alginate and carrageenan, into different formats and with adequate properties to sustain the viability of
encapsulated cells, envisioning their application as cell delivery vehicles for tissue regeneration. Different formulations of alginate
and carrageenan hydrogels and different processing parameters were considered to determine the best conditions required to
achieve the most adequate response in terms of the mechanical stability, cell viability, and functionality of the developed systems.
The morphology, size, and structure of the hydrogels and their degradation behavior and mechanical properties were evaluated
during this study. In addition to cytotoxicity studies, preliminary experiments were carried out to investigate the ability of
alginate−carrageenan beads/fibers to encapsulate chondrocytes. The results obtained indicated that the different formulations,
both in the form of beads and fibers, have considerable potential as cell-carrier materials for cell delivery in tissue engineering/
regenerative medicine applications.European NoE EXPERTISSUES - NMP3-CT-2004-500283Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/64070/2009
Validation of the patient assessment of chronic illness care (PACIC) short form scale in heart transplant recipients: The international cross-sectional bright study
Background: Transplant recipients are chronically ill patients, who require lifelong follow-up to manage co-morbidities and prevent graft loss. This necessitates a system of care that is congruent with the Chronic Care Model. The eleven-item self-report Patient Assessment of Chronic Illness Care (PACIC) scale assesses whether chronic care is congruent with the Chronic Care Model, yet its validity for heart transplant patients has not been tested. Methods: We tested the validity of the English version of the PACIC, and compared the similarity of the internal structure of the PACIC across English-speaking countries (USA, Canada, Australia and United Kingdom) and across six languages (French, German, Dutch, Spanish, Italian and Portuguese). This was done using data from the cross-sectional international BRIGHT study that included 1378 heart transplant patients from eleven countries across 4 continents. To test the validity of the instrument, confirmatory factor analyses to check the expected unidimensional internal structure, and relations to other variables, were performed. Results: Main analyses confirmed the validity of the English PACIC version for heart transplant patients. Exploratory analyses across English-speaking countries and languages also confirmed the single factorial dimension, except in Italian and Spanish. Conclusion: This scale could help healthcare providers monitor level of chronic illness management and improve transplantation care. Trial registration: Clinicaltrials.gov ID: NCT01608477, first patient enrolled in March 2012, registered retrospectively: May 30, 2012
- …