223 research outputs found

    Photoluminescence and concentration quenching of Pr3+ doped BaTa2O6 phosphor

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    The pure and Pr3+ doped TTB-BaTa2O6 phosphors were obtained by the solid state reaction method at 1 425 Β°C for 20hours. X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) analyses confirmed a single phase of BaTa2O6up to 10 mol % Pr2O36. SEM analysis also shows that BaTa2O6 grain size decreased with the increasing Pr2O36 concentration.The chemical composition of Pr3+ doped BaTa2O6 structures was confirmed by Energy Dispersive Spectroscopy(EDS) analysis. BaTa2O6:Pr3+ phosphors exhibited on a strong red emission at 620,9 nm, a green emission at 548,3 nm and a red emission at 655,2 nm. Emission intensity increased with Pr3+ doping concentration up to 1,5 mol %, then decreased due to concentration quenching

    Hematopoetic stem cell transplantation for solid tumors in Europe

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    Background: Hematopoetic stem cell transplants (HSCT) are discussed as treatment options for patients with solid tumors. Transplant numbers have changed substantially over the last decade, few controlled studies are available and different opinions prevail. Objective information on current practice is needed. Patients and methods: Data from 27 902 HSCT for solid tumors (2% allogeneic, 98% autologous), collected by the European Group for Blood and Marrow Transplantation (EBMT) activity survey from 1991 to 2002 were used to assess trends, transplant rates and coefficient of variation of transplant rates in Europe. Results: Transplant numbers increased from 536 in 1991 to 4154 in 1997 and decreased to 1913 in 2002. Indications were neuroblastoma (2504 HSCT; 9%), glioma (662 HSCT; 2%), soft tissue sarcoma (1253 HSCT; 4%), germ cell cancer (3291 HSCT; 12%), breast cancer (13 524 HSCT; 48%), Ewing's sarcoma (1896 HSCT; 7%), lung cancer (387 HSCT; 1%), ovarian cancer (845 HSCT; 3%) and other solid tumors (3540 HSCT; 14%). Allogeneic cells were used in <20 cases up to 1997; since then allogeneic HSCT increased to 159 in 2002, mainly for renal cell carcinoma. Low coefficients of variation in transplant rates (<60%) are observed for Ewing's sarcoma (<56.5%), suggesting consensus for this indication. Conclusions: These data give an overview on current practice of HSCT for solid tumors in Europe. They provide objective information for health-care providers and patient counsellin

    Autologous hematopoietic stem cell transplantation for breast cancer in Europe: Critical evaluation of data from the European Group for Blood and Marrow Transplantation (EBMT) Registry 1990-1999

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    The aim of this study was to identify trends in high-dose chemotherapy (HDC) with autologous hematopoietic stem cell transplantation (ASCT) and to assess survival in a large cohort of breast cancer (BC) patients receiving this therapy in Europe from 1990 to 1999. A total of 7471 patients who received HDC with ASCT between January 1, 1990 and December 31, 1999 were reported to the European Group for Blood and Marrow Transplantation Registry. Data required for demographics and survival analysis were available for 2679 patients with high-risk primary BC; 921 patients with inflammatory BC (IBC), and 2295 patients with metastatic disease. The main evaluation parameters were progression-free survival (PFS) and overall survival (OS). Between 1990 and 1998, autotransplants for BC increased 30-fold. Significant trends included use of blood-derived rather than marrow-derived stem cells, increment of reporting centers and decrease of mortality within 100 days from transplantation. The 5-year PFS and OS probabilities were 53 and 68% for high-risk disease and 42 and 53% for IBC, respectively. For metastatic disease 5-year PFS and OS probabilities in the whole cohort were 18 and 27%, respectively, while for women transplanted in complete remission the 5-year PFS was 29%. In conclusion, HDC with ASCT has been increasingly used until 1998 and the 100-day mortality rate has been constantly less than 2% from 1995 to date. The 5-year survival of high-risk BC is related to the number of axillary nodes involved at surgery. Outcome of patients with IBC is encouraging, suggesting the need for randomized trials. Patients with metastatic disease responding to pretransplant chemotherapy and harboring ER+ tumors have a better outcome

    Oil prices and stock returns : nonlinear links across sectors

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    We present evidence of an asymmetric relationship between oil prices and stock returns. The two regime multivariate Markov switching vector autoregressive (MSVAR) model allow us to capture the state shifts in the relationship between regional stock markets and sectors. Results suggest that oil price risk is significantly priced in the sample used. The impact is asymmetric with respect to market phases, and regimes have been associated with world economic, social and political events. Our study also suggests asymmetric responses of sector stock returns to oil price changes and different transmission impacts depending on the sector analyzed. There is a high causality from oil to sectors like Industrials and Oil & Gas. Companies inside the Utilities sector were more able to hedge against oil price increases between 2007 and 2012. Historical crisis events between 1992–1998 and 2003–2007 do not seem to have affected the relationship between oil and sector stock returns, given the higher probability of remaining smoother. For all sectors there seems to be a turn back to stability from 2012 onwards. Finally, investors gain more through portfolio diversification benefits built across, rather than within sectors.info:eu-repo/semantics/publishedVersio

    Sequential Valuation Networks: A New Graphical Technique for Asymmetric Decision Problems

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    This paper is a short (14-pp) version of a longer working paper titled "Sequential Valuation Networks for Asymmetric Decision Problems," University of Kansas School of Business Working Paper No. 286, January 2001, Revised June 2004, available from KU Scholarworks.This paper deals with representation and solution of asymmetric decision problems. We describe a new graphical representation called sequential valuation networks, which is a hybrid of Covaliu and Oliver’s sequential decision diagrams and Shenoy’s asymmetric valuation networks. Sequential valuation networks inherit many of the strengths of sequential decision diagrams and asymmetric valuation networks while overcoming many of their shortcomings. We illustrate our technique by representing and solving a modified version of Covaliu and Oliver’s Reactor problem

    Salvage high-dose chemotherapy for children with extragonadal germ-cell tumours

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    We reviewed the European Group for Blood and Marrow Transplantation (EBMT) experience with salvage high-dose chemotherapy (HDC) in paediatric patients with extragonadal germ-cell tumour (GCT). A total of 23 children with extragonadal GCT, median age 12 years (range 1–20), were treated with salvage HDC with haematopoietic progenitor cell support. The GCT primary location was intracranial site in nine cases, sacrococcyx in eight, retroperitoneum in four, and mediastinum in two. In all, 22 patients had a nongerminomatous GCT and one germinoma. Nine patients received HDC in first- and 14 in second- or third-relapse situation. No toxic deaths occurred. Overall, 16 of 23 patients (70%) achieved a complete remission. With a median follow-up of 66 months (range 31–173 months), 10 (43%) are continuously disease-free. Of six patients who had a disease recurrence after HDC, one achieved a disease-free status with surgical resection followed by chemotherapy and radiotherapy. In total, 11 patients (48%) are currently disease-free. Eight of 14 patients (57%) with extracranial primary and three of nine patients (33%) with intracranial primary GCT are currently disease-free. HDC induced impressive long-term remissions as salvage treatment in children with extragonadal extracranial GCTs. Salvage HDC should be investigated in prospective trials in these patients

    Busulphan is active against neuroblastoma and medulloblastoma xenografts in athymic mice at clinically achievable plasma drug concentrations

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    High-dose busulphan-containing chemotherapy regimens have shown high response rates in children with relapsed or refractory neuroblastoma, Ewing's sarcoma and medulloblastoma. However, the anti-tumour activity of busulfan as a single agent remains to be defined, and this was evaluated in athymic mice bearing advanced stage subcutaneous paediatric solid tumour xenografts. Because busulphan is highly insoluble in water, the use of several vehicles for enteral and parenteral administration was first investigated in terms of pharmacokinetics and toxicity. The highest bioavailability was obtained with busulphan in DMSO administered i.p. When busulphan was suspended in carboxymethylcellulose and given orally or i.p., the bioavailability was poor. Then, in the therapeutic experiments, busulphan in DMSO was administered i.p. on days 0 and 4. At the maximum tolerated total dose (50 mg kgβˆ’1), busulphan induced a significant tumour growth delay, ranging from 12 to 34 days in the three neuroblastomas evaluated and in one out of three medulloblastomas. At a dose level above the maximum tolerated dose, busulphan induced complete and partial tumour regressions. Busulphan was inactive in a peripheral primitive neuroectodermal tumour (PNET) xenograft. When busulphan pharmacokinetics in mice and humans were considered, the estimated systemic exposure at the therapeutically active dose in mice (113 ΞΌg h mlβˆ’1) was close to the mean total systemic exposure in children receiving high-dose busulphan (102.4 ΞΌg h mlβˆ’1). In conclusion, busulphan displayed a significant anti-tumour activity in neuroblastoma and medulloblastoma xenografts at plasma drug concentrations which can be achieved clinically in children receiving high-dose busulphan-containing regimens. 1999 Cancer Research Campaig

    Association between Selected Oral Pathogens and Gastric Precancerous Lesions

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    We examined whether colonization of selected oral pathogens is associated with gastric precancerous lesions in a cross-sectional study. A total of 119 participants were included, of which 37 were cases of chronic atrophic gastritis, intestinal metaplasia, or dysplasia. An oral examination was performed to measure periodontal indices. Plaque and saliva samples were tested with real-time quantitative PCR for DNA levels of pathogens related to periodontal disease (Porphyromonas gingivalis, Tannerella forsythensis, Treponema denticola, Actinobacillus actinomycetemcomitans) and dental caries (Streptococcus mutans and S. sobrinus). There were no consistent associations between DNA levels of selected bacterial species and gastric precancerous lesions, although an elevated but non-significant odds ratio (OR) for gastric precancerous lesions was observed in relation to increasing colonization of A. actinomycetemcomitans (ORβ€Š=β€Š1.36 for one standard deviation increase, 95% Confidence Intervalβ€Š=β€Š0.87–2.12), P. gingivalis (ORβ€Š=β€Š1.12, 0.67–1.88) and T. denticola (ORβ€Š=β€Š1.34, 0.83–2.12) measured in plaque. To assess the influence of specific long-term infection, stratified analyses by levels of periodontal indices were conducted. A. actinomycetemcomitans was significantly associated with gastric precancerous lesions (ORβ€Š=β€Š2.51, 1.13–5.56) among those with β‰₯ median of percent tooth sites with PDβ‰₯3 mm, compared with no association among those below the median (ORβ€Š=β€Š0.86, 0.43–1.72). A significantly stronger relationship was observed between the cumulative bacterial burden score of periodontal disease-related pathogens and gastric precancerous lesions among those with higher versus lower levels of periodontal disease indices (p-values for interactions: 0.03–0.06). Among individuals with periodontal disease, high levels of colonization of periodontal pathogens are associated with an increased risk of gastric precancerous lesions
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