1,308 research outputs found

    Supported Vanadium Oxide Catalysts: Quantitative Spectroscopy, Preferential Adsorption of V^4+/5+, and Al2O3 Coating of Zeolite Y

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    A series of supported vanadium oxide catalysts were prepared by the incipient wetness method as a function of the support composition (Al2O3, SiO2, and USY), the metal oxide loading (0-1 wt %), and the impregnation salt (vanadyl sulfate and ammonium vanadate). These catalysts have been studied by combined DRS-ESR spectroscopies in order to quantify the amount of V^4+ and V^5+ and to unravel their coordination geometries. These spectroscopic fingerprints have been used to study the preferential adsorption of V^4+/5+ ions on SiO2, Al2O3, and USY. Both V^4+ and V^5+ were preferentially adsorbed on Al2O3 and showed a much smaller pref-erence for USY and SiO2. The observed preference orders are discussed in relation with the properties of the support. In addition, a novel method is proposed to coat the external surface of USY with a thin film of Al2O3. The method is based on the deposition of USY with the so-called Keggin ion, [Al13O4(OH)24(H2O)12]7+ , which is too big to enter the USY channels or pores. The obtained Al2O3/USY material showed a preferential adsorption of V^4+ onto the Al2O3 film, suggesting that this method could be useful for vanadium passivation of FCC catalysts

    Towards an individualized management strategy for patients with chronic venous disease: Results of a Delphi consensus

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    Objective: To obtain consensus on management criteria for symptomatic patients with chronic venous disease (CVD; C2–C6) and superficial venous reflux. Method: We used a Delphi method by means of 36 statements sent by email to experts in the field of phlebology across the world over the course of three rounds. The statements addressed criteria for different venous treatments in patients with different characteristics (e.g. extensive comorbidities, morbid obesity and peripheral arterial disease). If at least 70% of the ratings for a specific statement were between 6 and 9 (agreement) or between 1 and 3 (disagreement), experts’ consensus was reached. Results: Twenty-five experts were invited to participate, of whom 24 accepted and completed all three rounds. Consensus was reached in 25/32 statements (78%). However, several statements addressing UGFS, single phlebectomies, patients with extensive comorbidities and morbid obesity remained equivocal. Conclusion: Considerable consensus was reached within a group of experts but also some gaps in available research were highlighted

    Immunohistochemical detection of somatostatin receptor subtypes sst1 and sst2A in human somatostatin receptor positive tumors

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    Although in situ hybridization has been used to examine the distribution of messenger RNA for somatostatin receptor subtypes (sst) in human tumors, the cellular localization of sst1 and sst2A receptors has not been reported. In this study, we describe the cellular localization of human sst1 and sst2A receptor proteins in both cryostat- and paraffin-embedded sections of 25 human tumor tissues using two recently developed polyclonal antibodies. Six somatostatin (SS) receptor (SSR) positive tumors (two gastrinomas, three carcinoids, one pheochromocytoma) and one SSR negative tumor (renal cell carcinoma), selected by positive and negative SSR autoradiography, respectively, were studied by both immunohistochemistry and Western blot analysis. The six SSR positive tumors expressed sst2A, while 4 of 5 expressed sst1 as well. The SSR negative tumor did not express either sst1 or sst2A. Western blot analysis of wheat germ agglutinin purified membrane proteins confirmed the presence of the sst1 and sst2A glycosylated receptors. The paraffin-embedded sections gave best information with respect to the subcellular localization. Sst1 immunoreactivity was observed both on the membrane and in the cytoplasm, while sst2A showed predominantly membrane-associated immunoreactivity. This subcellular distribution of sst1 or sst2A receptors was confirmed in paraffin-embedded sections of 8 additional intestinal carcinoids, 5 gastrinomas and 5 pheochromocytomas. Sst1 receptors were detected in 7 out of 8 carcinoids, in all gastrinomas, and in 4 out of 5 pheochromocytomas, while 6 out of 8 carcinoids, all gastrinomas, and 3 out of 5 pheochromocytomas expressed sst2A receptors. In conclusion, sst1 and sst2A receptors show a differential subcellular localization in human SSR positive tumors. The use of SSR subtype selective antibodies to detect the subcellular distribution of SSR subtypes in individual tumor cells is an important step forward to understand more about the pathophysiological role of the different SSR subtypes in human tumors

    Cost-analysis of treatment of childhood acute lymphoblastic leukemia with asparaginase preparations: The impact of expensive chemotherapy

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    __Abstract__ Asparaginase is an expensive drug, but important in childhood acute lymphoblastic leukemia. In order to compare costs of PEGasparaginase, Erwinia asparaginase and native E. coli asparaginase, we performed a cost-analysis in the Dutch Childhood Oncology Group ALL-10 medium-risk group intensification protocol. Treatment costs were calculated based on patient level data of 84 subjects, and were related to the occurrence of allergy to PEGasparaginase. Simultaneously, decision tree and sensitivity analyses were conducted. The total costs of the intensification course of 30 weeks were 57,893inpatientswithoutPEGasparaginaseallergy(n=64).Thecostsweresignificantlyhigher(57,893 in patients without PEGasparaginase allergy (n=64). The costs were significantly higher (113,558) in case of allergy (n=20) necessitating a switch to Erwinia asparaginase. Simulated scenarios (decision tree analysis) using native E. coli asparaginase in intensification showed that the costs of PEGasparaginase were equal to those of native E. coli asparaginase. Also after sensitivity analyses, the costs for PEGasparaginase were equal to those of na

    Automated Selection of Hotspots (ASH): enhanced automated segmentation and adaptive step finding for Ki67 hotspot detection in adrenal cortical cancer

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    BACKGROUND: In prognosis and therapeutics of adrenal cortical carcinoma (ACC), the selection of the most active areas in proliferative rate (hotspots) within a slide and objective quantification of immunohistochemical Ki67 Labelling Index (LI) are of critical importa

    The Stability of Problem Behavior Across the Preschool Years: An Empirical Approach in the General Population

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    This study examined the stability of internalizing and externalizing problems from age 1.5 to 6 years, while taking into account developmental changes in the presentation of problems. The study comprised a population-based cohort of 7,206 children (50.4 % boys). At ages 1.5, 3, and 6 years, mothers reported on problem behavior using the Child Behavior Checklist/1.5-5 (CBCL/1.5-5). At each age we performed latent profile analysis on the CBCL/1.5-5 scales. Latent transition analysis (LTA) was applied to study the stability of problem behavior. Profiles of problem behavior varied across ages. At each age, 82–87 % of the children did not have problems whereas approximately 2 % showed a profile of co-occurring internalizing and externalizing problems. This profile was more severe (with higher scores) at 6 years than at earlier ages. A predominantly internalizing profile only emerged at 6 years, while a profile with externalizing problems and emotional reactivity was present at each age. LTA showed that, based on profiles at 1.5 and 3 years, it was difficult to predict the type of profile at 6 years. Children with a profile of co-occurring internalizing and externalizing problems early in life were most likely to show problem behavior at 6 years. This study shows that the presentation of problem behavior changes across the preschool period and that heterotypic continuity of problems is very common among preschoolers. Children with co-occurring internalizing and externalizing problems were most likely to show persisting problems. The use of evidence-based treatment for these young children may prevent psychiatric problems across the life course

    The value of plasma markers for the clinical behaviour of phaeochromocytomas

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    OBJECTIVE: Phaeochromocytomas (PCCs) are widely known for their clinical unpredictability. This study intends to define predictive plasma markers for their variable postoperative behaviour. Furthermore, the diagnostic accuracy of these plasma tests was determined. DESIGN AND METHODS: A retrospective correlative study was performed in a series of 83 operated and four autopsied patients in order to correlate preoperative catecholamine (CAT) levels of 103 PCCs with their clinical behaviour. In a subset of cases, chromogranin-A (Chr-A) and enzymes/precursors of the CAT biosynthesis were studied for their predictive value. RESULTS: Basal CAT levels were elevated in 81/87 instances (sensitivity: 93%). Four of six cases with normal measurements showed only medullary hyperplasia. Larger PCCs, particularly those showing necrosis, capsular and vascular invasion, secreted higher CAT levels. Bilateral, hereditary tumours were less productive than their unilateral counterparts. Extra-adrenal PCCs secreted significantly lower levels of epinephrine (EPI) than intra-adrenal tumours. Fourteen patients developed metastases. According to Kaplan-Meier estimations, patients with higher levels of dopamine, norepinephrine (NE) and aromatic l-amino acid decarboxylase as well as lower ratios of EPI/EPI+NE, had significantly shorter metastases-free intervals. Existence of preoperative hypertension, left ventricular hypertrophy and measured blood pressures showed significant positive relationships with CAT levels, but not with Chr-A. CONCLUSIONS: These data showed that plasma CAT measurement is a sensitive method in the diagnostic work-up of PCCs. Those tumours producing normal levels are commonly small and asymptomatic. Furthermore, certain secretion patterns are indicative of the presence of metastases as well as the size and site of spor

    Nuclear Eg5 (kinesin spindle protein) expression predicts docetaxel response and prostate cancer aggressiveness

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    Novel biomarkers predicting prostate cancer (PCa) aggressiveness and docetaxel therapy response of PCa patients are needed. In this study the correlation between nuclear Eg5-expression, PCa docetaxel response and PCa aggressiveness was assessed. Immunohistochemical staining for nuclear Eg5 was performed on 117 archival specimens from 110 PCa patients treated with docetaxel between 2004 and 2012. Samples were histologically categorized as positive/negative. Median follow-up time from diagnosis was 11.6 years. Nuclear Eg5-expression was significantly related to docetaxel response (p=0.036) in tissues acquired within three years before docetaxel initiation. Nuclear Eg5-expression was not related to Gleason-score (p=0.994). Survival of patients after docetaxel initiation did not differ based on nuclear Eg5-expression (p=0.540). Analyzing samples taken before hormonal therapy, overall survival and time to docetaxel use were significantly decreased in patients with nuclear Eg5-expressing tumors (p<0.01). Eg5-positive nuclei were found more frequently in T4-staged tumors (p=0.04), Gleason 8-10 tumors (p=0.08), and in metastasized tumors (p<0.01). Multivariate analyses indicated that nuclear Eg5-expression may be an independent parameter for tumor aggressiveness. Limitations of a retrospective analysis apply. In conclusion, nuclear Eg5-expression may be a predictive biomarker for docetaxel response in metastatic castrate-resistant PCa patients and a prognostic biomarker for hormone-naive PCa patients. Prospective validation studies are needed

    HI in the Outskirts of Nearby Galaxies

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    The HI in disk galaxies frequently extends beyond the optical image, and can trace the dark matter there. I briefly highlight the history of high spatial resolution HI imaging, the contribution it made to the dark matter problem, and the current tension between several dynamical methods to break the disk-halo degeneracy. I then turn to the flaring problem, which could in principle probe the shape of the dark halo. Instead, however, a lot of attention is now devoted to understanding the role of gas accretion via galactic fountains. The current Λ\rm \Lambda cold dark matter theory has problems on galactic scales, such as the core-cusp problem, which can be addressed with HI observations of dwarf galaxies. For a similar range in rotation velocities, galaxies of type Sd have thin disks, while those of type Im are much thicker. After a few comments on modified Newtonian dynamics and on irregular galaxies, I close with statistics on the HI extent of galaxies.Comment: 38 pages, 17 figures, invited review, book chapter in "Outskirts of Galaxies", Eds. J. H. Knapen, J. C. Lee and A. Gil de Paz, Astrophysics and Space Science Library, Springer, in pres
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