287 research outputs found
The impact of SCIAMACHY near-infrared instrument calibration on CH4 and CO total columns
The near-infrared spectra measured with the SCIAMACHY instrument on board the ENVISAT satellite suffer from several instrument calibration problems. The effects of three important instrument calibration issues on the retrieved methane (CH4) and carbon monoxide (CO) total columns have been investigated: the effects of the growing ice layer on the near-infrared detectors, the effects of the orbital variation of the instrument dark signal, and the effects of the dead/bad detector pixels. Corrections for each of these instrument calibration issues have been defined. The retrieved CH4 and CO total columns including these corrections show good agreement with CO measurements from the MOPITT satellite instrument and with CH4 model calculations by the chemistry transport model TM3. Using a systematic approach, it is shown that all three instrument calibration issues have a significant effect on the retrieved CH4 and CO total columns. However, the impact on the CH4 total columns is more pronounced than for CO, because of its smaller variability. Results for three different wavelength ranges are compared and show good agreement. The growing ice layer and the orbital variation of the dark signal show a systematic, but time-dependent effect on the retrieved CH4 and CO total columns, whereas the effect of the dead/bad pixels is rather unpredictable: some dead pixels show a random effect, some more systematic, and others no effect at all. The importance of accurate corrections for each of these instrument calibration issues is illustrated using examples where inaccurate corrections lead to a wrong interpretation of the results
Tumor necrosis is associated with increased alphavbeta3 integrin expression and poor prognosis in nodular cutaneous melanomas
<p>Abstract</p> <p>Background</p> <p>Tumor necrosis and apoptotic activity are considered important in cancer progression, but these features have not been much studied in melanomas. Our hypothesis was that rapid growth in cutaneous melanomas of the vertical growth phase might lead to tissue hypoxia, alterations in apoptotic activity and tumor necrosis. We proposed that these tumor characteristics might be associated with changes in expression of cell adhesion proteins leading to increased invasive capacity and reduced patient survival.</p> <p>Methods</p> <p>A well characterized series of nodular melanoma (originally 202 cases) and other benign and malignant melanocytic tumors (109 cases) were examined for the presence of necrosis, apoptotic activity (TUNEL assay), immunohistochemical expression of hypoxia markers (HIF-1 α, CAIX, TNF-α, Apaf-1) and cell adhesion proteins (α<sub>v</sub>β<sub>3 </sub>integrin, CD44/HCAM and osteopontin). We hypothesized that tumor hypoxia and necrosis might be associated with increased invasiveness in melanoma through alterations of tumor cell adhesion proteins.</p> <p>Results</p> <p>Necrosis was present in 29% of nodular melanomas and was associated with increased tumor thickness, tumor ulceration, vascular invasion, higher tumor proliferation and apoptotic index, increased expression of α<sub>v</sub>β<sub>3 </sub>integrin and poor patient outcome by multivariate analysis. Tumor cell apoptosis did also correlate with reduced patient survival. Expression of TNF-α and Apaf-1 was significantly associated with tumor thickness, and osteopontin expression correlated with increased tumor cell proliferation (Ki-67).</p> <p>Conclusion</p> <p>Tumor necrosis and apoptotic activity are important features of melanoma progression and prognosis, at least partly through alterations in cell adhesion molecules such as increased α<sub>v</sub>β<sub>3 </sub>integrin expression, revealing potentially important targets for new therapeutic approaches to be further explored.</p
Memberships and CM Diagrams of the Open Cluster NGC 7243
The results of astrometric and photometric investigations of the open cluster
NGC 7243 are presented. Proper motions of 2165 stars with root-mean-square
error of 1.1 mas/yr were obtained by means of PDS scanning of astrometric
plates covering the time interval of 97 years. A total of 211 cluster members
down to V=15.5 mag have been identified. V and B magnitudes have been
determined for 2118 and 2110 stars respectively. Estimations of mass (348Mo < M
< 522Mo), age (t=2.5x10^8 yr), distance (r=698 pc) and reddening (E(B-V)=0.24)
of the cluster NGC 7243 have been made.Comment: 24 pages, 15 figures. Submitted to Astronomy and Astrophysic
Ki-67 expression is superior to mitotic count and novel proliferation markers PHH3, MCM4 and mitosin as a prognostic factor in thick cutaneous melanoma
<p>Abstract</p> <p>Background</p> <p>Tumor cell proliferation is a predictor of survival in cutaneous melanoma. The aim of the present study was to evaluate the prognostic impact of mitotic count, Ki-67 expression and novel proliferation markers phosphohistone H3 (PHH3), minichromosome maintenance protein 4 (MCM4) and mitosin, and to compare the results with histopathological variables.</p> <p>Methods</p> <p>202 consecutive cases of nodular cutaneous melanoma were initially included. Mitotic count (mitosis per mm<sup>2</sup>) was assessed on H&E sections, and Ki-67 expression was estimated by immunohistochemistry on standard sections. PHH3, MCM4 and mitosin were examined by staining of tissue microarrays (TMA) sections.</p> <p>Results</p> <p>Increased mitotic count and elevated Ki-67 expression were strongly associated with increased tumor thickness, presence of ulceration and tumor necrosis. Furthermore, high mitotic count and elevated Ki-67 expression were also associated with Clark's level of invasion and presence of vascular invasion. High expression of PHH3 and MCM4 was correlated with high mitotic count, elevated Ki-67 expression and tumor ulceration, and increased PHH3 frequencies were associated with tumor thickness and presence of tumor necrosis. Univariate analyses showed a worse outcome in cases with elevated Ki-67 expression and high mitotic count, whereas PHH3, MCM4 and mitosin were not significant. Tumor cell proliferation by Ki-67 had significant prognostic impact by multivariate analysis.</p> <p>Conclusions</p> <p>Ki-67 was a stronger and more robust prognostic indicator than mitotic count in this series of nodular melanoma. PHH3, MCM4 and mitosin did not predict patient survival.</p
ESA's wind Lidar mission ADM-AEOLUS; on-going scientific activities related to calibration, retrieval and instrument operation
The Earth Explorer Atmospheric Dynamics Mission
(ADM-Aeolus) of ESA will be the first-ever satellite to
provide global observations of wind profiles from
space. Its single payload, namely the Atmospheric
Laser Doppler Instrument (ALADIN) is a directdetection
high spectral resolution Doppler Wind Lidar
(DWL), operating at 355 nm, with a fringe-imaging
receiver (analysing aerosol and cloud backscatter) and a
double-edge receiver (analysing molecular backscatter).
In order to meet the stringent mission requirements on
wind retrieval, ESA is conducting various science
support activities for the consolidation of the on-ground
data processing, calibration and sampling strategies.
Results from a recent laboratory experiment to study
Rayleigh-Brillouin scattering and improve the
characterisation of the molecular lidar backscatter
signal detected by the ALADIN double-edge Fabry-
Perot receiver will be presented in this paper. The
experiment produced the most accurate ever-measured
Rayleigh-Brillouin scattering profiles for a range of
temperature, pressure and gases, representative of
Earth’s atmosphere. The measurements were used to
validate the Tenti S6 model, which is implemented in
the ADM-Aeolus ground processor.
First results from the on-going Vertical Aeolus
Measurement Positioning (VAMP) study will be also
reported. This second study aims at the optimisation of
the ADM-Aeolus vertical sampling in order to
maximise the information content of the retrieved
winds, taking into account the atmospheric dynamical
and optical heterogeneity. The impact of the Aeolus
wind profiles on Numerical Weather Prediction (NWP)
and stratospheric circulation modelling for the different
vertical sampling strategies is also being estimated
Coordinated Transcription of Key Pathways in the Mouse by the Circadian Clock
AbstractIn mammals, circadian control of physiology and behavior is driven by a master pacemaker located in the suprachiasmatic nuclei (SCN) of the hypothalamus. We have used gene expression profiling to identify cycling transcripts in the SCN and in the liver. Our analysis revealed ∼650 cycling transcripts and showed that the majority of these were specific to either the SCN or the liver. Genetic and genomic analysis suggests that a relatively small number of output genes are directly regulated by core oscillator components. Major processes regulated by the SCN and liver were found to be under circadian regulation. Importantly, rate-limiting steps in these various pathways were key sites of circadian control, highlighting the fundamental role that circadian clocks play in cellular and organismal physiology
A systematic review of strategies to recruit and retain primary care doctors
Background There is a workforce crisis in primary care. Previous research has looked at the reasons underlying recruitment and retention problems, but little research has looked at what works to improve recruitment and retention. The aim of this systematic review is to evaluate interventions and strategies used to recruit and retain primary care doctors internationally. Methods A systematic review was undertaken. MEDLINE, EMBASE, CENTRAL and grey literature were searched from inception to January 2015.Articles assessing interventions aimed at recruiting or retaining doctors in high income countries, applicable to primary care doctors were included. No restrictions on language or year of publication. The first author screened all titles and abstracts and a second author screened 20%. Data extraction was carried out by one author and checked by a second. Meta-analysis was not possible due to heterogeneity. Results 51 studies assessing 42 interventions were retrieved. Interventions were categorised into thirteen groups: financial incentives (n=11), recruiting rural students (n=6), international recruitment (n=4), rural or primary care focused undergraduate placements (n=3), rural or underserved postgraduate training (n=3), well-being or peer support initiatives (n=3), marketing (n=2), mixed interventions (n=5), support for professional development or research (n=5), retainer schemes (n=4), re-entry schemes (n=1), specialised recruiters or case managers (n=2) and delayed partnerships (n=2). Studies were of low methodological quality with no RCTs and only 15 studies with a comparison group. Weak evidence supported the use of postgraduate placements in underserved areas, undergraduate rural placements and recruiting students to medical school from rural areas. There was mixed evidence about financial incentives. A marketing campaign was associated with lower recruitment. Conclusions This is the first systematic review of interventions to improve recruitment and retention of primary care doctors. Although the evidence base for recruiting and care doctors is weak and more high quality research is needed, this review found evidence to support undergraduate and postgraduate placements in underserved areas, and selective recruitment of medical students. Other initiatives covered may have potential to improve recruitment and retention of primary care practitioners, but their effectiveness has not been established
Phage inducible islands in the gram-positive cocci
The SaPIs are a cohesive subfamily of extremely common phage-inducible chromosomal islands (PICIs) that reside quiescently at specific att sites in the staphylococcal chromosome and are induced by helper phages to excise and replicate. They are usually packaged in small capsids composed of phage virion proteins, giving rise to very high transfer frequencies, which they enhance by interfering with helper phage reproduction. As the SaPIs represent a highly successful biological strategy, with many natural Staphylococcus aureus strains containing two or more, we assumed that similar elements would be widespread in the Gram-positive cocci. On the basis of resemblance to the paradigmatic SaPI genome, we have readily identified large cohesive families of similar elements in the lactococci and pneumococci/streptococci plus a few such elements in Enterococcus faecalis. Based on extensive ortholog analyses, we found that the PICI elements in the four different genera all represent distinct but parallel lineages, suggesting that they represent convergent evolution towards a highly successful lifestyle. We have characterized in depth the enterococcal element, EfCIV583, and have shown that it very closely resembles the SaPIs in functionality as well as in genome organization, setting the stage for expansion of the study of elements of this type. In summary, our findings greatly broaden the PICI family to include elements from at least three genera of cocci
Discontinuation of anti-PD-1 antibody therapy in the absence of disease progression or treatment limiting toxicity : clinical outcomes in advanced melanoma
Background Programmed cell death protein 1 (PD-1) blocking monoclonal antibodies improve the overall survival of patients with advanced melanoma but the optimal duration of treatment has not been established. Patients and Methods This academic real-world cohort study investigated the outcome of 185 advanced melanoma patients who electively discontinued anti-PD-1 therapy with pembrolizumab (N=167) or nivolumab (N=18) in the absence of disease progression (PD) or treatment limiting toxicity (TLT) at 14 medical centres across Europe and Australia. Results Median time on treatment was 12months (range 0.7-43). The best objective tumour response at the time of treatment discontinuation was complete response (CR) in 117 (63%) patients, partial response (PR) in 44 (24%) patients and stable disease (SD) in 16 (9%) patients; 8 (4%) patients had no evaluable disease (NE). After a median follow-up of 18months (range 0.7-48) after treatment discontinuation, 78% of patients remained free of progression. Median time to progression was 12months (range 2-23). PD was less frequent in patients with CR (14%) compared with patients with PR (32%) and SD (50%). Six out of 19 (32%) patients who were retreated with an anti-PD-1 at the time of PD obtained a new antitumour response. Conclusions In this real-world cohort of advanced melanoma patients discontinuing anti-PD-1 therapy in the absence of TLT or PD, the duration of anti-PD-1 therapy was shorter when compared with clinical trials. In patients obtaining a CR, and being treated for >6months, the risk of relapse after treatment discontinuation was low. Patients achieving a PR or SD as best tumour response were at higher risk for progression after discontinuing therapy, and defining optimal treatment duration in such patients deserves further study. Retreatment with an anti-PD-1 at the time of progression may lead to renewed antitumour activity in some patients. Clinical trial registration NCT02673970 (https://clinicaltrials.gov/ct2/show/NCT02673970?cond=melanoma&cntry=BE&city=Jette&rank=3)Peer reviewe
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