677 research outputs found

    Deep CCD Surface Photometry of the Edge-On Spiral NGC 4244

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    We have obtained deep surface photometry of the edge-on spiral galaxy NGC 4244. Our data reliably reach 27.5 R magnitude arcsec^{-2}, a significant improvement on our earlier deep CCD surface photometry of other galaxies. NGC 4244 is a nearby Scd galaxy whose total luminosity is approximately one magnitude fainter than the peak of the Sc luminosity function. We find that it has a simple structure: a single exponential disk, with a scale height h_Z = 246 +/- 2 pc, a scale length h_R = 1.84 +/- 0.02 kpc and a disk cutoff at a radius R(max) = 10.0 kpc (5.4 scale lengths). We confirm a strong cutoff in the stellar disk at R(max), which happens over only 1 kpc. We do not see any statistically significant evidence for disk flaring with radius. Unlike the more luminous Sc galaxies NGC 5907 and M 33, NGC 4244 does not show any evidence for a second component, such as a thick disk or halo, at mu(R) < 27.5 magnitude arcsec^{-2}.Comment: 36 pages, including 12 figures; accepted for publication in Sept 99 A

    Giant deer (Megaloceros giganteus) diet from Mid-Weichselian deposits under the present North Sea inferred from molar-embedded botanical remains

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    The molar of a giant deer, Megaloceros giganteus (Blumenbach, 1799), was discovered in sandy deposits of the North Sea, about 10 km west of the present shoreline of the Netherlands. Compacted masticated plant remains were preserved in the molar's deep folds. A palaeoecological analysis of these plant remains shows the complete dominance of pollen from Artemisia (sage) and other Asteraceae Tubuliflorae (Compositae), indicating that the animal foraged in a steppe environment, and may have preferred to eat Artemisia, which contain a high level of nutrients such as calcium and phosphorous components, which are important for antler building. Radiocarbon dating indicates that the plant remains are of mid‐Weichselian age [38 570 (+300, −290) 14C a BP, Greenland Interstadial‐11]. This is the first study of the food choice of M. giganteus based on palaeoecological evidence. We hypothesize about links between the extirpation of M. giganteus at the onset of the Holocene in North‐West Europe and the transition from a landscape with highly dynamic geomorphological processes and consequently prevalence of immature and nutrient‐rich soils, to a less dynamic landscape with stable, leached and acidifying soils, and the decline of Artemisia and other calciphilous plants

    Oxidation of cellulose in pressurized carbon dioxide

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    This work presents first results upon oxidation of type II cellulose by nitrogen dioxide dissolved in carbon dioxide at high pressure. This reaction leads to oxidized cellulose, a natural-based bioresorbable fabric used for biomedical applications. The oxidation reaction takes place in a heterogeneous fluid–solid system. Kinetics of oxidation is presented here and effects of operating conditions such as pressure, temperature and initial moisture content of cellulose are investigated. Results are presented in terms of degree of oxidation of cellulose and quality of the final oxidized cellulose, which has been characterized using liquid-state and solid-state 13C NMR. The experimental results show the existence of possible secondary reactions which may lead to oxidized cellulose with insufficient mechanical strength. An attempt is made to evidence and understand the role of CO2 as a solvent in this system. Indeed, although supercritical CO2 appears to be a suitable candidate as a solvent for oxidation reactions, some inhibiting effect on nitrogen dioxide activity are observed in this case

    Expression of a retinoic acid signature in circulating CD34 cells from coronary artery disease patients

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    <p>Abstract</p> <p>Background</p> <p>Circulating CD34+ progenitor cells have the potential to differentiate into a variety of cells, including endothelial cells. Knowledge is still scarce about the transcriptional programs used by CD34+ cells from peripheral blood, and how these are affected in coronary artery disease (CAD) patients.</p> <p>Results</p> <p>We performed a whole genome transcriptome analysis of CD34+ cells, CD4+ T cells, CD14+ monocytes, and macrophages from 12 patients with CAD and 11 matched controls. CD34+ cells, compared to other mononuclear cells from the same individuals, showed high levels of KRAB box transcription factors, known to be involved in gene silencing. This correlated with high expression levels in CD34+ cells for the progenitor markers HOXA5 and HOXA9, which are known to control expression of KRAB factor genes. The comparison of expression profiles of CD34+ cells from CAD patients and controls revealed a less naĂŻve phenotype in patients' CD34+ cells, with increased expression of genes from the Mitogen Activated Kinase network and a lowered expression of a panel of histone genes, reaching levels comparable to that in more differentiated circulating cells. Furthermore, we observed a reduced expression of several genes involved in CXCR4-signaling and migration to SDF1/CXCL12.</p> <p>Conclusions</p> <p>The altered gene expression profile of CD34+ cells in CAD patients was related to activation/differentiation by a retinoic acid-induced differentiation program. These results suggest that circulating CD34+ cells in CAD patients are programmed by retinoic acid, leading to a reduced capacity to migrate to ischemic tissues.</p

    Shared Decision Making in Health Care Visits for CKD:Patients’ Decisional Role Preferences and Experiences

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    Rationale &amp; Objective: Research on shared decision making (SDM) in chronic kidney disease (CKD) has focused almost exclusively on the modality of kidney replacement treatment. We explored what other CKD decisions are recognized by patients, what their preferences and experiences are regarding these decisions, and how decisions are made during their interactions with medical care professionals. Study Design: Cross-sectional study. Setting &amp; Participants: Patients with CKD receiving (outpatient) care in 1 of 2 Dutch hospitals. Exposure: Patients’ preferred decisional roles for treatment decisions were measured using the Control Preferences Scale survey administered after a health care visit with medical professionals. Outcome: Number of decisions for which patients experienced a decisional role that did or did not match their preferred role. Observed levels of SDM and motivational interviewing in audio recordings of health care visits, measured using the 4-step SDM instrument (4SDM) and Motivational Interviewing Treatment Integrity coding tools.Analytical Approach: The results were characterized using descriptive statistics, including differences in scores between the patients’ experienced and preferred decisional roles. Results: According to the survey (n = 122) patients with CKD frequently reported decisions regarding planning (112 of 122), medication changes (82 of 122), or lifestyle changes (59 of 122). Of the 357 reported decisions in total, patients preferred that clinicians mostly (125 of 357) or fully (101 of 357) make the decisions. For 116 decisions, they preferred a shared decisional role. For 151 of 357 decisions, the patients’ preferences did not match their experiences. Decisions were experienced as “less shared/patient-directed” (76 of 357) or “more shared/patient-directed” (75 of 357) than preferred. Observed SDM in 118 coded decisions was low (median 4; range, 0 – 22). Motivational interviewing techniques were rarely used. Limitations: Potential recall and selection bias, and limited generalizability. Conclusions: We identified multiple discrepancies between preferred, experienced, and observed SDM in health care visits for CKD. Although patients varied in their preferred decisional role, a large minority of patients expressed a preference for shared decision making for many decisions. However, SDM behavior during the health care visits was observed infrequently. Plain-Language Summary: Shared decision making (SDM) may be a valuable approach for common chronic kidney disease (CKD) decisions, but our knowledge is limited. We collected patient surveys after health care visits for CKD. Patients most frequently experienced decisions regarding planning, medication, and lifestyle. Three decisional roles were preferred by comparable numbers of patients: let the clinician alone decide, let the clinician decide for the most part, or “equally share” the decision. Patients’ experiences of who made the decision did not always match their preferences. In audio recordings of the health care visits, we observed low levels of SDM behavior. These findings suggest that the preference for “sharing decisions” is often unmet for a large number of patients.</p

    Predicting outcomes in chronic kidney disease:needs and preferences of patients and nephrologists

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    Introduction: Guidelines on chronic kidney disease (CKD) recommend that nephrologists use clinical prediction models (CPMs). However, the actual use of CPMs seems limited in clinical practice. We conducted a national survey study to evaluate: 1) to what extent CPMs are used in Dutch CKD practice, 2) patients’ and nephrologists’ needs and preferences regarding predictions in CKD, and 3) determinants that may affect the adoption of CPMs in clinical practice. Methods: We conducted semi-structured interviews with CKD patients to inform the development of two online surveys; one for CKD patients and one for nephrologists. Survey participants were recruited through the Dutch Kidney Patient Association and the Dutch Federation of Nephrology. Results: A total of 126 patients and 50 nephrologists responded to the surveys. Most patients (89%) reported they had discussed predictions with their nephrologists. They most frequently discussed predictions regarded CKD progression: when they were expected to need kidney replacement therapy (KRT) (n = 81), and how rapidly their kidney function was expected to decline (n = 68). Half of the nephrologists (52%) reported to use CPMs in clinical practice, in particular CPMs predicting the risk of cardiovascular disease. Almost all nephrologists (98%) reported discussing expected CKD trajectories with their patients; even those that did not use CPMs (42%). The majority of patients (61%) and nephrologists (84%) chose a CPM predicting when patients would need KRT in the future as the most important prediction. However, a small portion of patients indicated they did not want to be informed on predictions regarding CKD progression at all (10–15%). Nephrologists not using CPMs (42%) reported they did not know CPMs they could use or felt that they had insufficient knowledge regarding CPMs. According to the nephrologists, the most important determinants for the adoption of CPMs in clinical practice were: 1) understandability for patients, 2) integration as standard of care, 3) the clinical relevance. Conclusion: Even though the majority of patients in Dutch CKD practice reported discussing predictions with their nephrologists, CPMs are infrequently used for this purpose. Both patients and nephrologists considered a CPM predicting CKD progression most important to discuss. Increasing awareness about existing CPMs that predict CKD progression may result in increased adoption in clinical practice. When using CPMs regarding CKD progression, nephrologists should ask whether patients want to hear predictions beforehand, since individual patients’ preferences vary.</p

    Prognostic value and kinetics of circulating endothelial cells in patients with recurrent glioblastoma randomised to bevacizumab plus lomustine, bevacizumab single agent or lomustine single agent. A report from the Dutch Neuro-Oncology Group BELOB trial

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    Background:Angiogenesis is crucial for glioblastoma growth, and anti-vascular endothelial growth factor agents are widely used in recurrent glioblastoma patients. The number of circulating endothelial cells (CECs) is a surrogate marker for endothelial damage. We assessed their kinetics and explored their prognostic value in patients with recurrent glioblastoma.Methods:In this side study of the BELOB trial, 141 patients with recurrent glioblastoma were randomised to receive single-agent bevacizumab or lomustine, or bevacizumab plus lomustine. Before treatment, after 4 weeks and after 6 weeks of treatment, CECs were enumerated.Results:The number of CECs increased during treatment with bevacizumab plus lomustine, but not during treatment in the single-agent arms. In patients treated with lomustine single agent, higher absolute CEC numbers after 4 weeks (log 10 CEC hazard ratio (HR) 0.41, 95% CI 0.18-0.91) and 6 weeks (log 10 CEC HR 0.16, 95% CI 0.05-0.56) of treatment were associated with improved overall survival (OS). Absolute CEC numbers in patients receiving bevacizumab plus lomustine or bevacizumab single agent were not associated wit
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